Arizona philanthropists found bound and burned in posh suburban home

(CBS/KPHO/AP) PARADISE VALLEY, Ariz. - Phoenix couple Lawrence and Glenna Shapiro's bodies were found bound and burned Monday after their upscale suburban home went up in flames.

CBS affiliate KPHO reports Dr. Shapiro and his wife were well-known philanthropists in the area. Police have been unusually tight-lipped about their murder investigation.

"It looks to me like the Shapiros were targeted. Someone had to actually locate them, see where they live and find them and commit the crime," said Paul Huebl, a private investigator. He believes police may have a person of interest.

A Paradise Valley police commander said the agency had contacted the U. S. Marshals and the U.S. Secret Service.

Paradise Valley officers went to the home Monday morning after Phoenix police found a the couple's car on fire behind a strip mall about 20 miles away.

When an officer arrived at the house, she saw smoke coming from inside. Firefighters put out fires that had been set in two bedrooms, including the master bedroom, where the Shapiros' bodies were found.

Because the bodies were burned beyond recognition, coroners had to use dental records to identify the couple, who are both reportedly in their 70s.

The crime has shaken Paradise Valley residents who were told to lock their doors and be aware of their surrounds. Police have not investigated a homicide there since 2004.

Investigators have no suspects and have not determined a motive.

The Shapiros started their own charitable organization in 2010 and have actively supported many local civic organizations and charities.