HOUSTON -- Harris County officials have identified more than 100 vehicles sitting at the bottoms of Brays and Sims Bayous.

This week they started fishing them out of the water. Police say many of the vehicles are believed to have been used in criminal activity.

"[Each vehicle] is treated like a potential crime scene," said Harris County Flood Control District outreach coordinator Sandra Ortiz.

The submerged-vehicle removal program started with a pilot program in 2016 during which 20 cars were extracted from Brays Bayou over 10 days.

Most of the cars recovered last year had been reported stolen. Houston Police determined one of the cars was used during an armed robbery in 1999.

Another extracted vehicle was used in a 2000 home-invasion armed robbery.

Some of them stem from crimes that are even older.

"The oldest vehicle was a 1978 Datsun,” Ortiz said. “It was reported stolen in 1982, so yeah, 34 years."

Five cars were recovered on Thursday and two on Wednesday.

Police have not said if they have identified any of those vehicles as ones used in criminal activity.

The project is scheduled to continue for the next two months and county officials ultimately hope to pull 65 cars from Brays and Sims Bayous.

Just over $218,000 was allocated to fund the project and county officials are hopeful the recoveries will not only help to solve crimes, but also assist in the removal of potential environmental hazards from Houston’s waterways.

“Because of all the toxins and chemicals that these vehicles could be releasing into our bayous,” Ortiz explained.