Two Fresno police detectives are searching full time for a bandit who has robbed or tried to rob at least eight pharmacies of the drug Oxycontin since October, including four Tuesday.

The robber presents a note demanding the drug and warns he is armed, said Sgt. Dave Ramos of the department's Street Violence Unit. The robber probably is an addict, and he may also be dealing drugs, Ramos said. That may be why he struck four stores in one night.

"He's so persistent. When he didn't get any [Oxycontin] in Fresno, he went to Clovis. So he needs a fix," Ramos said. He added the robber probably sells any extra drugs he obtains.

On Tuesday, the bandit first tried to rob the Vons grocery store at 8949 N. Cedar Ave., and Save Marts at Champlain Drive and Perrin Avenue, and at First Street and Nees Avenue. The pharmacies didn't have Oxycontin, so he next struck the Walgreen's drugstore at Villa and Shaw avenues in Clovis, where he apparently obtained the drug.

"It was the same guy," said Ramos, after conferring with Clovis police.

That followed robberies last week at a Rite Aid at 6074 N. First St., and at three Walgreen's -- on Dec. 4 at 7015 N. West Ave.; Nov. 9 at 6885 N. Willow Ave.; and Oct. 4 at 2840 W. Ashlan Ave.

The bandit is white, 20 to 30 years old and 6 feet tall with a thin or medium build. In the most recent robberies, he was wearing a black baseball cap, a black jacket, a black hooded sweatshirt, tennis shoes and prescription glasses. He should be considered armed and dangerous, and citizens should not attempt to apprehend him, police said.

Anyone with information is asked to call detectives Ed Dingler at (559) 621-2423, Dennis Krug at (559) 621-2424 or Crime Stoppers at (559) 498-STOP, where a reward may be available if it leads to an arrest.