In the summertime, when long and warm days prompt cul-de-sac ballgames and evening lawn-mowing sessions, Loudoun County authorities know to expect a spike in reports of golf clubs, tools and the occasional case of beer pinched from open garages.

The garage thefts usually die down with cooler fall weather and the start of school. But for a month starting in late October, they began again -- and they were different.

At least seven times, intruders entered homes in Sterling and Ashburn through garages -- usually left open -- and stole credit cards from purses left near doors or inside unlocked cars. In another case, credit cards were stolen from a car in a Sterling driveway. In all cases, the credit cards were used in buying sprees.

Loudoun investigators got a break Nov. 22, when Herndon police called to say they had arrested Reston resident Jimmie M. McCray, 21, and a 17-year-old male at a Foot Locker store, where the two allegedly tried to use a credit card stolen in one of the Sterling burglaries.

Now Loudoun authorities say they think the two men are linked to many of the other Sterling thefts, most of which took place within a one-mile circle, investigator Michael Hall said.

"There's a lot of different investigations going on all over Northern Virginia . . . involving these same guys," Hall said.

McCray and the juvenile will be charged with a Nov. 17 burglary in the 20000 block of Canal Crossing Court in Sterling, Hall said. In that case, a woman pulled her vehicle into her garage and went inside her home about 3 p.m., leaving the garage door open, her car unlocked and her purse on the front seat.

The purse was missing when the woman came out about 5:45 p.m., Hall said.

That evening, the woman filed a police report -- and the thieves went on a shopping trip with her credit cards, Hall said. The cards were used at several stores, including Kay Jewelers at Dulles Town Center, where one card was used to pay for a $772 watch. A watch police found on McCray was identified by the store as the one it sold, Hall said.

Authorities think that on Nov. 21, McCray and the juvenile hit Sterling again. Two credit cards and a laptop computer were stolen from a vehicle parked in a driveway in the 22000 block of Rock Hill Road, Hall said.

The victim noticed the thefts the next day but did not report them, Hall said. One of the man's cards was used a day after the burglary for $254 in spending at a Loudoun Wal-Mart, Hall said.

That night, at the Herndon Foot Locker, authorities said, McCray and the juvenile tried to use one of the woman's credit cards, which by then had been blocked from use. Store officials tipped off police, who found the pair in possession of the Sterling man's two cards and a stolen Honda sedan, authorities said.

After he was arrested in Herndon, McCray was also charged in Fairfax County with robbery, malicious wounding and grand larceny stemming from an incident in August, said Herndon Police Sgt. Darcy L. Burns.

The Loudoun thefts underscore the need for residents to lock garages and cars, even on what seem to be tranquil, suburban streets, authorities said.

"I see it in my neighborhood almost every night when I go home -- people leaving their garages open, thinking this is still the country," Hall said.