Investigators are looking into whether two men arrested for the robbery and killings of seven people in their Richmond homes were involved in similar crimes elsewhere, a police spokeswoman said Sunday.

Ray Joseph Dandridge and Ricky Gray, both 28, were captured Saturday in Philadelphia on charges stemming from the killings of members of two families, including two children, who were discovered bound with tape. The home of one family was set on fire and the other was ransacked.

Authorities said police found evidence linking the pair to all seven murders.

After the arrests, the investigation widened.

"There's other law enforcement agencies that are looking into any similarities with these cases," said Cynthia Price, a spokeswoman for Richmond police. "We know there was a home invasion in Chesterfield and they have been charged with that one."

Police in suburban Chesterfield County did not immediately respond to phone calls seeking comment Sunday about charges in the Jan. 3 home invasion, in which no one was injured.

Dandridge had been released from a state prison in November after serving 10 years for robbery.

"We all make mistakes and what don't kill will only make us stronger," Dandridge wrote on a Web site from prison. "I believe in treating others as I want to be treated and respected in life."

A SWAT team found Dandridge and Gray on Saturday and used pepper spray to subdue one of the men, who resisted arrest, said Philadelphia police Capt. Benjamin Naish.

The men remained in custody Sunday in Philadelphia, Naish said. An extradition hearing could be held as early as Monday.

Police said they were led to the suspects by a green Chevrolet Blazer taken from the site of a triple homicide discovered Friday.

The bodies of Percyell Tucker, 55; his wife, Mary Tucker, 47, and her daughter, Ashley Baskerville, 21, were found in their ransacked home. The causes of death have not been disclosed.

Price would not comment on media reports that the suspects knew one of the victims in the Tucker home.

Mary Tucker worked at a laundry and regularly attended Fifth Baptist Church, said Rosa Tillar, a friend and co-worker. "She was a nice, quiet person. She stayed to herself mostly."

The murders in the Tucker home came less than a week after the slayings of members of a family well-known in music and business circles. Bryan Harvey, 49; his wife, Kathryn, 39, and their daughters, Stella, 9, and Ruby, 4, were found with their throats cut on New Year's Day. Their house was set on fire.

Price said it appeared that the Harveys were random victims of a robbery.

Bryan Harvey was a guitarist and singer who played in several rock bands, most notably the duo House of Freaks, which released five albums on three labels from 1987 to 1995.

Kathryn Harvey co-owned a toy and novelty store in Carytown, a 12-block stretch of trendy boutiques, cafes and coffee shops just west of downtown Richmond. She was the half-sister of actor Steven Culp, who played Rex Van De Kamp on "Desperate Housewives."