CLEARWATER — A Pinellas sheriff's deputy resigned Monday over a series of misconduct incidents, including allegations that he picked up a prostitute.

An internal investigation found that Deputy Robert F. Johnson lied to detectives about his actions on Sept. 12, when Clearwater police saw him pick up a prostitute. The deputy also violated agency policy by leaving work early and telling his ex-wife she was the subject of a drug investigation.

On Sept. 12, Clearwater police surveilling a prostitute watched as Johnson picked up the woman. Officers stopped the car. Johnson told them he was a deputy who was giving the woman a ride home. He said he was driving in the area when he saw the woman running and waving her hands like she was trying to get away from someone.

Two Clearwater police detectives testified that the woman never showed signs of distress and that Johnson's behavior led them to believe he was going to ask her for sex. They decided not to arrest him.

On Sept. 15, Johnson searched for his ex-wife, Michelle Licavoli, in a sheriff's database. He saw that she was being investigated for charges of doctor shopping and told her about it, officials said. Licavoli, 41, was arrested five days later. Last week, she was placed in a pre-trial intervention program, according to court records.

The same day of his ex-wife's arrest, St. Petersburg police were conducting surveillance on Johnson for reasons that are unclear.

That morning, officers saw him drive home 30 minutes before the end of his shift. He changed out of his uniform in his driveway and drove his daughter to school in his cruiser. Johnson later admitted to doing the same thing multiple times.

Though none of the incidents resulted in criminal charges, authorities said his actions damaged his integrity, could have compromised a criminal investigation and jeopardized officer safety. Sheriff's officials said he would have been fired had he not resigned.

It also wasn't the first time he had been in trouble.

In August, Johnson was the subject of an internal review after another prostitute claimed he had offered her a ride home in his cruiser while she stood outside the Pinellas County Court Complex. The woman accepted, and on the way home, Johnson stopped and bought her cigarettes, a report states.

Johnson was also disciplined for a 2011 violation related to numerous visits he made to the home of a Seminole woman while he was on patrol.

During one visit, a neighbor dispute took place in the area, but Johnson did not respond to the call.

Johnson had worked for the Sheriff's Office since 1999.