Similarities among several recent robberies in Delaware County and Philadelphia have led police to what they believe is a ring of thieves that may have been targeting Asian victims in dozens of holdups over a two-year period - crimes that investigators once thought were unrelated.

State police arrested two men yesterday in connection with one of the robberies, but police said they had many "people of interest," including some they are questioning and some at large.

Detectives believe the thieves sometimes followed business owners home and other times targeted drivers of expensive cars.

"These guys were basically surfing for victims on Delaware County roads," said Capt. David Young of the Pennsylvania State Police.

Delaware County District Attorney G. Michael Green said the break came in the last two days as state police probed an armed robbery in Middletown Township last Saturday, when two men allegedly robbed a husband and wife around 10 p.m. as the couple returned to their home in the 200 block of Lenni Road. The robbers tried to steal the victims' Mercedes-Benz and fled with their wallet, purse and wedding rings, according to police.

On Wednesday, TD Bank contacted police about online purchases made with stolen bank cards and shipped to the address of Shawn Davis, 18, of the 7900 block of Caesar Place, Philadelphia. Police said Davis confessed to the robbery and named Charon Humphrey, 18, of the 7500 block of Wheeler Street in Philadelphia as an accomplice.

Davis and Humphrey were charged with robbery and aggravated assault, along with weapons and related charges. They have not been charged in the other holdups.

The most recent robbery occurred just before 3 a. m. yesterday when two intruders entered an apartment above a restaurant in the 500 block of MacDade Boulevard, Collingdale.

Police Chief Robert Adams said the two masked men used a ladder to gain roof access and then forced open a second-story window to the apartment.

The victims, a couple who left Fujian province in China 10 years ago, have worked at the restaurant, owned by the woman's brother, for five years.

The woman, 42, said she and her husband were sleeping about 3 a.m. when they heard a knock at a bedroom window. The two men in ski masks forced their way through the window, pointed a gun at her husband's forehead, and demanded money.

The woman said she started to cry and told them she didn't speak much English. She gave them $100 or $120 and told them, "Money for you. You go, you go."

Her husband struggled with the one of the men in the hallway and one of the suspects fired his gun, punching a fist-size hole in the wall near the floorboard. The men fled through the window, she said.

In two Marple Township robberies this week, Asian business owners were accosted by three men using weapons.

The first incident occurred on Monday between 8:45 and 9 p.m. when the intruders forced their way through a sliding glass door at a home in the 400 block of Hampshire Drive. Inside, they tied up a 66-year-old man and his 64-year-old wife, ransacked the home, and left with money, jewelry and a fur coat. The victims freed themselves after the robbers left and called police.

The second incident happened late Wednesday evening in the 100 block of Ferguson Avenue. A 51-year-old Asian woman with a business in Upper Darby thought she was being followed home, but lost sight of the car by the time she arrived at her house. As she walked to a back door, two men approached and grappled with her for her briefcase. The victim's 15-year-old son tried to assist his mother and was pushed to the ground. The suspects left with the briefcase, which contained cash, and jumped into a waiting car driven by another suspect.

In both cases, the intruders were armed with handguns.

Police do not believe the Nov. 10 murder in Upper Darby of Hoa Pham, 60, a former member of the South Vietnamese army, is connected to the robberies.

Pham was killed and his wife severely beaten by an intruder who broke into the couple's Copley Road home and demanded money.

The reward for information leading to an arrest in that case is now $12,000, according to police.

Contact staff writer Mari A. Schaefer at 610-892-9149 or mschaefer@phillynews.com.