WELD COUNTY, Colo. -- A private investigator who does what many P.I.s do -- surveillance -- has been charged with stalking.

Timothy Allan Stitt, 42, was arrested by LaSalle police on charges of stalking after he allegedly put a tracking device on the car of Shantele Sherman.

In an arrest warrant obtained by 7NEWS, Officer David Miller, Jr. said Stitt admitted putting a black GPS device under Sherman's car. (Read the arrest warrant here.)

Stitt told the officer he had been following Sherman for two weeks because her husband, Jeffrey Schudel, had hired him. The couple was going through a divorce and were in a child-custody dispute.

Chris Bray, past president of the Professional Private Investigators Association of Colorado, told 7NEWS he's concerned that Stitt is being charged with a crime that requires malicious intent.

"It's huge precedence," Bray said. "If investigators are going to be held to the standard of stalking in the performance of their job, then we've got a lot of issues as far as our livelihood."