HOUSTON -- Four employees in the office of Houston Mayor Pro Tem Carol Alvarado were removed from their jobs Wednesday in connection with improper bonuses totaling $130,000, KPRC Local 2 reported.

Officials said the investigation began after the city's finance director received reports of payroll irregularities.

Office of Inspector General agents and Houston police raided the offices shortly after lunchtime.

The employees were immediately placed on paid administrative leave. Computers were confiscated from the office, and door locks and card keys were changed.

"The matter concerns improper bonuses that were brought to my attention by the director of finance administration (Tuesday) night," Mayor Bill White said. "These were all four employees of the mayor pro tem's office, which is a permanent office within city council, which supports activities of the city council staff."

White said the four city workers apparently shared $130,000 in bonuses, which was far beyond any bonus allowed in city government. He said two workers each took $50,000 by circumventing the entire payroll approval process.

"That's improper. Period," White said. "It's a betrayal of public trust. This isn't our money. It's the public's money. We will follow it through to the full extent of the law."

The employees were making between $40,000 and $75,000.

Criminal charges are expected. More people could be implicated as well.

The mayor said that there was no sign that Alvarado had anything to do with the irregularities.

"I was disturbed to learn of this irregularity that has been reported. I am cooperating completely. I want a very thorough and complete investigation," Alvarado said. "No members of my council district staff are involved with this investigation."

The office of inspector general is responsible for investigating any allegations of wrongdoing for city employees.