A man charged with sexual assault in the Aspen Hill area Wednesday night is not a suspect in a series of such assaults that have occurred there over the last 18 months, Montgomery County police said yesterday.

James Edward Flanagan, 29, of Silver Spring, was arrested after he allegedly rammed his Jeep into one police car and collided with another in his attempt to flee the scene of an assault earlier in the evening.

But Detective Donald A. Hutchison, one of four investigators working on the 16 other sexual attacks in the area, said, "There are no strong links connecting Flanagan to the other sexual assault cases."

After receiving a call about 7:05 p.m. Wednesday about a sexual assault in the Bel Pre Road-Norbeck Road area, police stopped a Jeep at Georgia Avenue and Heathfield Road. An officer said that as he walked toward the vehicle, the driver put it into reverse and rammed the police cruiser. A chase ensued, ending when the jeep crashed head-on with another police car in the 4000 block of Southend Road, police said.

Hutchison said that Flanagan, who is being held without bond at the Montgomery County Detention Center, does not fit the physical description of the Aspen Hill attacker and that the procedures used to carry out the latest assault were not the same.

The assault with which Flanagan is charged occurred on the street and the victim was a young woman apparently hitchhiking, Hutchison said. The 16 other victims have all been attacked in single-family homes, he said.