Manhunt on for N.H. murder suspect spotted in Fla.

St. Petersburg, Fla. -- Authorities say a man who is suspected of killing his parents and setting their house on fire in New Hampshire is believed to be in the Tampa Bay, Florida, area.

St. Petersburg police and the U.S. Marshals Service on Tuesday said that Matthew Thomas Dion has been in the St. Petersburg area since late March and was last seen earlier this month.

New Hampshire investigators have been looking for the 38-year-old Dion since the bodies of his parents were found after an explosion and fire March 24 at the Manchester home they shared with him.

The death certificates filed in Hillsborough County Probate Court show that Robert Dion, 71, and Constance Dion, 67, were strangled with a wire on March 19. The medical examiner's report said they died within minutes and listed their deaths as homicides. Investigators concluded the fire was intentionally set.

Authorities in New Hampshire obtained arrest warrants charging Matthew Dion with two counts of second-degree murder and arson.

Also, three counts of possession of child pornography were filed against him in April. Investigators sifting through the charred home found evidence linking Dion to the material.

Federal marshals in Florida said Tuesday that Dion was last seen the first week in September, and that he stole a silver 2013 Hyundai Elantra, with the Florida tag of G673WH. They say there have been sightings of him in the Tampa-St. Petersburg area since late March.

Police told CBS affiliate WTSP that Dion befriended a woman in St. Petersburg and had been living with her under an alias for months. She reportedly told police that she noticed money missing from her accounts, and the car Dion allegedly stole belonged to her.

The U.S. Marshals Service in May posted a $5,000 reward for information leading to Dion's location and arrest.

Law enforcement officials say Dion has an extensive background and familiarity with the southeastern region of the country, particularly Florida and Atlanta, Georgia. Marshals say he is believed to be armed and dangerous. Anyone spotting him should notify law enforcement officials and not attempt to apprehend him.

The Marshals say Dion should be considered armed and dangerous, and may be suicidal.

Tips about Matthew Dion's whereabouts can be reported to the U.S. Marshal's Fugitive Task Force at 603-225-1632 or by calling 1-877-WANTED-2.