Investigators trying to figure out what led up to the death of a beloved Clearwater elderly couple aren't showing their cards just yet.

CLEARWATER, Fla. -- The homicide of David and Mina Swan last weekend in their Clearwater home was not a random crime, police said Friday.

Amid what's been about a week-long investigation, enough evidence shows "that the offender came to kill," Chief Daniel Slaughter told the media during a news conference.

However, police remain tight-lipped as to what detectives have found so far.

David, 88, and his wife, 80-year-old Mina Swan, were found shot to death Saturday in their Clearwater home on Flushing Avenue. Since then, police have announced they have no known suspects -- but are tracking leads.

The Clearwater Police Department has set up a tip line hotline for the homicide case at (727) 562-4141.

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Slaughter said there's a specific, 24-hour window of time investigators are analyzing. The Swans last were seen around 3 p.m. on Sept. 27, and police are trying to figure out what happened from that point into the following day.

Among the people being questioned include family and friends -- anyone who might have spoken to the couple.

"We know that in murder cases, there's some form of a victim, offender relationship," Slaughter said. "...[A suspect] went there to murder this nice, elderly couple. I can't tell you why yet, but I'm going to work pretty hard trying to."

Slaughter says there's no current danger to the public.

The investigation began last weekend, he said, and will continue until detectives solve the case.

Mina Swan's daughter, Noel Devine, said the couple loved to explore the world and the country. She said the family would become "a little stressed" when they would take off in their RV with bad tires, but Dave and Mina were never worried; they got along with people, and everyone loved them.

"Our family is devastated by this loss," Devine said. "Mom and Dave loved life. They just came back from their second trip to Iceland."

Anyone with more information on this case is asked to call police at 727-562-4242.

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