OK, here we go.
"Peace Officer, as defined by TPC 1.07(a)(36):
(36) "Peace officer" means a person elected, employed,
or appointed as a peace officer under Article 2.12, Code of Criminal
Procedure, Section 51.212 or 51.214, Education Code, or other law.
Sounds simple enough, huh? Now to delve into the Code of Criminal Procedure.
TCCP 2.12:
Art. 2.12. WHO ARE PEACE OFFICERS. The following are peace
officers:
(1) sheriffs, their deputies, and those reserve deputies
who hold a permanent peace officer license issued under Chapter
1701, Occupations Code;
(2) constables, deputy constables, and those reserve deputy
constables who hold a permanent peace officer license issued under
Chapter 1701, Occupations Code;
(3) marshals or police officers of an incorporated city,
town, or village, and those reserve municipal police officers who
hold a permanent peace officer license issued under Chapter 1701,
Occupations Code;
(4) rangers and officers commissioned by the Public Safety
Commission and the Director of the Department of Public Safety;
(5) investigators of the district attorneys', criminal
district attorneys', and county attorneys' offices;
(6) law enforcement agents of the Texas Alcoholic Beverage
Commission;
(7) each member of an arson investigating unit commissioned
by a city, a county, or the state;
(8) officers commissioned under Section 37.081, Education
Code, or Subchapter E, Chapter 51, Education Code;
(9) officers commissioned by the General Services
Commission;
(10) law enforcement officers commissioned by the Parks and
Wildlife Commission;
(11) airport police officers commissioned by a city with a
population of more than 1.18 million that operates an airport that
serves commercial air carriers;
(12) airport security personnel commissioned as peace
officers by the governing body of any political subdivision of this
state, other than a city described by Subdivision (11), that
operates an airport that serves commercial air carriers;
(13) municipal park and recreational patrolmen and security
officers;
(14) security officers and investigators commissioned as
peace officers by the comptroller;
(15) officers commissioned by a water control and
improvement district under Section 49.216, Water Code;
(16) officers commissioned by a board of trustees under
Chapter 54, Transportation Code;
(17) investigators commissioned by the Texas State Board of
Medical Examiners;
(18) officers commissioned by the board of managers of the
Dallas County Hospital District, the Tarrant County Hospital
District, or the Bexar County Hospital District under Section
281.057, Health and Safety Code;
(19) county park rangers commissioned under Subchapter E,
Chapter 351, Local Government Code;
(20) investigators employed by the Texas Racing Commission;
(21) officers commissioned under Chapter 554, Occupations
Code;
(22) officers commissioned by the governing body of a
metropolitan rapid transit authority under Section 451.108,
Transportation Code, or by a regional transportation authority
under Section 452.110, Transportation Code;
(23) investigators commissioned by the attorney general
under Section 402.009, Government Code;
(24) security officers and investigators commissioned as
peace officers under Chapter 466, Government Code;
(25) an officer employed by the Texas Department of Health
under Section 431.2471, Health and Safety Code;
(26) officers appointed by an appellate court under
Subchapter F, Chapter 53, Government Code;
(27) officers commissioned by the state fire marshal under
Chapter 417, Government Code;
(28) an investigator commissioned by the commissioner of
insurance under Article 1.10D, Insurance Code;
(29) apprehension specialists commissioned by the Texas
Youth Commission as officers under Section 61.0931, Human Resources
Code;
(30) officers appointed by the executive director of the
Texas Department of Criminal Justice under Section 493.019,
Government Code;
(31) investigators commissioned by the Commission on Law
Enforcement Officer Standards and Education under Section
1701.160, Occupations Code;
(32) commission investigators commissioned by the Texas
Commission on Private Security under Section 1702.061(f),
Occupations Code;
(33) the fire marshal and any officers, inspectors, or
investigators commissioned by an emergency services district under
Chapter 775, Health and Safety Code; and
(34) officers commissioned by the State Board of Dental
Examiners under Section 254.013, Occupations Code, subject to the
limitations imposed by that section.
Long, but no mention of feds yet. But there's still the Education Code.
TEC 51.212:
Sec. 51.212. PEACE OFFICERS AT PRIVATE INSTITUTIONS. (a) The governing boards of private institutions of higher education, including private junior colleges, are authorized to employ and commission peace officers for the purpose of enforcing:
(1) state law on the campuses of private institutions of higher education; and
(2) state and local law, including applicable municipal ordinances, at other locations, as permitted by Subsection (b) or Section 51.2125.
(b) Any officer commissioned under the provisions of this section is vested with all the powers, privileges, and immunities of peace officers if the officer:
(1) is on the property under the control and jurisdiction of the respective private institution of higher education or is otherwise performing duties assigned to the officer by the institution, regardless of whether the officer is on property under the control and jurisdiction of the institution, but provided these duties are consistent with the educational mission of the institution and are being performed within a county in which the institution has land; or
(2) to the extent authorized by Section 51.2125, is:
(A) requested by another law enforcement agency to provide assistance in enforcing state or local law, including a municipal ordinance, and is acting in response to that request; or
(B) otherwise assisting another law enforcement agency in enforcing a law described by Paragraph (A).
(c) Any officer assigned to duty and commissioned shall take and file the oath required of peace officers, and shall execute and file a good and sufficient bond in the sum of $1,000, payable to the governor, with two or more good and sufficient sureties, conditioned that the officer will fairly, impartially, and faithfully perform the duties as may be required of the officer by law. The bond may be sued on from time to time in the name of the person injured until the whole amount is recovered.
(d) The governing boards of private institutions of higher education are authorized to hire and pay on a regular basis peace officers commissioned by an incorporated city. The officers shall be under the supervision of the hiring institution, but shall be subject to dismissal and disciplinary action by the city. An incorporated city is authorized to contract with a private institution of higher education for the use and employment of its commissioned officers in any manner agreed to, provided that there is no expense incurred by the city.
(e) In this section, "private institution of higher education" means a private or independent institution of higher education as defined by Section 61.003.
And TEC 51.214:
Sec. 51.214. SECURITY OFFICERS FOR MEDICAL CORPORATIONS IN CERTAIN MUNICIPALITIES. (a) In any municipality with a population of 1.18 million or more, the governing board of a private, nonprofit medical corporation that provides security services for an institution of higher education or a private postsecondary educational institution and other entities located within the same medical complex, or that provides security services for a branch of that medical corporation, may employ and commission security personnel to enforce the law of this state within the jurisdiction designated by Subsection (c).
(b) An officer commissioned under this section may make arrests and has all the powers, privileges, and immunities of a peace officer while performing the officer's assigned duties within the jurisdiction designated by Subsection (c). An officer assigned to duty and commissioned shall take and file the oath required of peace officers and shall execute and file a good and sufficient bond in the sum of $1,000, payable to the governor, with two or more good and sufficient sureties, conditioned that the officer will fairly, impartially, and faithfully perform the duties required of the officer by law. The bond may be sued on from time to time in the name of the person injured until the whole amount is recovered.
(c) The jurisdiction of an officer commissioned under this section is limited to:
(1) property owned, leased, managed, or controlled by the medical corporation; and
(2) a street or alley that abuts the property or an easement in or a right-of-way over or through the property.
(d) An officer commissioned by a medical corporation under this section is not entitled to compensation or benefits provided by this state or a political subdivision of this state.
(e) The state or a political subdivision of this state is not liable for an act or omission of an officer commissioned under this section during the performance of the officer's assigned duties.
(f) A medical corporation may not commission a person under this section unless the person obtains a peace officer license issued by the Commission on Law Enforcement Officer Standards and Education. The medical corporation shall pay to the Commission on Law Enforcement Officer Standards and Education on behalf of an employee any fees that are necessary to obtain a required license.
(g) A person's commission and any authority to act as an officer under this section are automatically revoked if the person's employment with a medical corporation is terminated for any reason.
Wee! So, there's no reference to any federal officer. Only state, county, and city-level officers are defined as peace officers as far as Texas is concerned.