Two Dallas police majors, including one who had been accused of misconduct related to her test-prep business, were fired Thursday during an internal-affairs hearing, the department said.

Police Chief U. Renee Hall fired Maj. LaToya Porter and Maj. Paulette Richardson, who had both been on administrative leave for months over allegations of "inappropriate action related to assessment center," according to police records obtained by The Dallas Morning News.

Porter had been accused of adverse conduct over concerns that she had helped shape the exam officers take to be promoted to sergeant while running a test-prep business that helped clients prepare for the same exam.

Former Dallas officer LaToya Porter (center) was promoted to the rank of major in 2016. (Dallas Police Department)

An internal investigation found that Porter had engaged in adverse conduct when she served as a subject-matter expert for the sergeant assessment examination and provided sergeant assessment training to clients through her test-prep business between Oct. 17 and Oct. 29, 2017, the Dallas Police Department said in a statement Thursday.

Lt. Mike Igo said at a civil service meeting in February that Porter had "privileged access to all test material."

Police found that Porter had created a conflict of interest when she represented one of her clients, who was a candidate for promotion to sergeant, in a civil-service matter.

Richardson was fired after an investigation determined she accepted a gift or gratuity from a subordinate employee between Oct. 13 and Oct. 15, 2017.

WFAA-TV (Channel 8) obtained documents that showed Richardson took money from officers to prep for the sergeant exam. Later, she showed up at a domestic-violence call in an attempt to return the money, and an officer told investigators Richardson called officers and asked them to delete emails and text messages from her, WFAA reported.

Both Richardson and Porter interfered with the integrity of an administrative investigation on Nov. 16, 2017, police said. The department didn't elaborate on how they interfered.

Porter's attorney said previously that she had not given her clients an advantage over other officers taking the test.

Both officers were promoted to major, the rank below deputy chief, in 2016.

Lieutenant LaToya Porter, #8486, is promoting to the rank of Major. pic.twitter.com/2cub5uiRAx — Dallas Police Dept (@DallasPD) August 30, 2016

Major Paulette Richardson, #7512 pic.twitter.com/0jYrPBjjsi — Dallas Police Dept (@DallasPD) October 6, 2016

Richardson was hired in May 1997 and was assigned to the northwest patrol division. Porter was hired in February 2004 and was assigned to the north central patrol division.

Neither officer can appeal her discipline, as police majors are considered "exempt" employees, the department said in a statement.

At the February civil service board meeting, the board decided to throw out the results of the sergeant exam that officers took in November 2017, deeming it unfair. Officers who took it then would have to try again later, officials said.

Earlier this week, Hall fired two other officers after investigations concluded that one, an 11-year veteran of the department, had harassed a resident in person and through calls and text messages. The other was fired after being arrested on a DWI charge in June.