Frustrated that a seemingly unmistakable target has eluded their grasp for two months, area police agencies asked the public yesterday to help them track down a 6-foot-9 man who has robbed at least 16 grocery stores, and then slipped swiftly into the night.

The man, whom police have nicknamed the "Stretch Bandit," has robbed supermarkets in Alexandria and Prince William, Prince George's, Montgomery, Loudoun and Fairfax counties, all since Aug. 9. The latest robbery occurred at a Super Fresh store in Silver Spring.

"He's not like the typical criminal who fits into the crowd," said Officer Boyd Thompson, a spokesman for the Fairfax police. "It's amazing someone that big can keep going when we know who he is, without getting caught."

Yesterday, Fairfax police announced a $1,000 reward for the suspect, whom police have identified as Tyrone Jethro Wyche, 41. His last known address was in the 1600 block of Duke Street, Alexandria. Police have asked anyone who might have information to call Crime Solvers at 1-800-673-2777.

Arrest warrants for Wyche have been issued in Fairfax, Montgomery and Prince George's counties. Police said Wyche was identified through investigation and would not reveal the specifics of what led to him. They declined to say whether he had a previous record.

Police said they can't explain how or why the man has been so elusive. "He keeps hitting and hitting and we can't catch him," Thompson said.

Authorities said there is no pattern to the path the man takes; he seems to show up at stores throughout the area.

Police said a man fitting the description eluded Montgomery police Wednesday night after he robbed the Super Fresh Store. A police officer stopped a man fitting the description. When the officer ordered the man out of the truck he was driving, the man drove off. The officer chased the truck a few blocks, but the man got out of the truck and fled.

"I guess at 6-foot-9, he has a pretty good stride," said Detective M.E. Crosbie, who investigates robberies in Prince William, where a man fitting the description was stopped in a stolen car on Sept. 20 but ran away from police. "Why haven't we caught him? Why haven't they found Jimmy Hoffa? That's a good question. It's just the way it's worked so far," Crosbie said.

Police say the man's approach to the robberies is similar in most cases. He walks into the store and either buys something or waits until a cashier opens a register drawer. He keeps one hand in his pocket and indicates he has a gun. He grabs the money and flees. Police say there have been no injuries.

In Fairfax, police said the man has hit four stores since Aug. 9, including Giant, Shoppers Food Warehouse and Safeway. Montgomery police said the suspect has hit six stores there. The suspect has robbed at least one Giant store in Prince George's, police said. All the robberies have occurred between 5 p.m. and 11 p.m., police said.

Crosbie said the area's police departments discovered they were all looking for the same 6-foot-9 robber when investigators met at a monthly robbery meeting yesterday. Crosbie said investigators discussed the cases and showed a picture of the suspect.

"This guy stands out like a sore thumb," said Sgt. Chuck Cooke, of the Prince George's police. "It's kind of hard to maintain a low profile when you're 6-9, 230-odd pounds."

Staff writer Veronica T. Jennings contributed to this report.