TAMPA — A Tampa police detective was fired Thursday amid a federal grand jury investigation into potential criminal conduct, police Chief Jane Castor said.

Detective Eric Houston, who worked on some of the department's highest profile cases, was dismissed several weeks after a department investigator found Houston was involved in suspected criminal activity, Castor said. She refused to give specifics about the accusations but said the information was turned over to the U.S. Attorney's Office.

"It's clear that Houston's alleged criminal behavior is so egregious that it's necessary to take this step immediately," Castor said. "His actions do not represent the good men and women of this organization, and he does not deserve to wear the uniform of the Tampa Police Department."

The agency launched an internal investigation of Houston in October in what Castor said was "an abundance of caution" after his wife, La Joyce Houston, was fired from the Tampa Police Department based on welfare fraud allegations.

Police said they had caught La Joyce Houston, then a 16-year department veteran making $91,400 a year, conspiring to use a jail inmate's food stamps. The inmate, Rita Girvin, is the biological mother of a girl La Joyce Houston adopted years ago.

At the time the department began investigating Eric Houston, there was no reason to suspect he knew about or was involved in any wrongdoing, the chief said.

Then, on April 3, a detective in the department's Criminal Intelligence Bureau found evidence that Houston was involved in illegal activities, Castor said.

Police offered few details about the evidence, citing a provision that keeps federal grand jury proceedings confidential until an indictment is issued.

Houston was immediately put on administrative leave after the evidence was uncovered, Castor said. The investigation was handed to federal prosecutors.

On Thursday morning, Castor met with representatives of the U.S. Attorney's Office, who told her about the progress of a grand jury investigation. Afterward, she decided to fire Houston. A formal disciplinary notice declared the detective was in violation of the department's regulations on conformance to laws and standard of conduct.

"This couldn't be any more disheartening to me," Castor said. "When you have an officer who goes against the oath of office, it reflects negatively on every other officer."

There is no link between Eric Houston's dismissal and his wife's case, Castor said. La Joyce Houston is charged with grand theft and food stamp fraud.

The U.S. Attorney's Office confirmed that Eric Houston is being investigated, but gave no details. The Tampa Police Department received a grand jury subpoena Thursday for Houston's personnel records, including his date of hire, internal affairs files, complaints, misconduct reports and personnel actions. Houston, 53, was a 24-year employee who spent a decade as a homicide detective.

The department has reviewed 19 open cases that Houston helped investigate, including three in which he was the lead detective. The defendants in those cases are:

• James Jugo — Accused of manslaughter in the February death of his roommate, Benjamin Calderon, 56, who was beaten after the two argued about stolen food, according to police. Police reinterviewed witnesses in the Jugo case after Houston's dismissal, Castor said.

• Maurice K. Johnson Jr. — Found incompetent to stand trial last year on charges of shooting a pizza delivery man during a robbery, according to police.

• Steven M. Hevia — Charged in a drug-related case in which a man died while under the influence of a psychedelic substance he reportedly bought from Hevia, according to police.

Other cases Houston helped investigate include those of: Julie Schenecker, who goes to trial next week on charges that she shot her two children to death at their New Tampa home; and Dontae Morris, who was convicted of killing two Tampa police officers.

Investigators found no evidence that the accusations were related to Houston's work in any police case, Castor said. They also don't believe the situation will affect the cases as they move toward trial.

But, the chief said, the investigation is still ongoing.

The matter is the latest in a string of internal scandals for the department. They include the September firing of Sgt. Ray Fernandez. He was accused of lying about his role in the DUI arrest of Tampa lawyer C. Philip Campbell, which prosecutors later determined was a setup involving a rival law firm.

Houston could not be reached for comment and his attorney, Wade Whidden, would not comment Thursday.

Owen Kohler, general counsel for the Tampa Police Benevolent Association, said the organization was still trying to gather information.

"We don't really know the specifics of what he's accused of," Kohler said. "I know that he maintains his innocence."

Times staff writer Anna Phillips and researcher John Martin contributed to this report. Dan Sullivan can be reached at (813) 226-3386 or dsullivan@tampabay.com.