IONIA, Mich. (WZZM) - A man who spent 26 in prison for the arson deaths of his wife and two young daughters is suing Ionia County police and prosecutors for obstruction of justice and malicious prosecution stemming from a 1986 conviction based on faulty evidence.

David Gavitt was sentenced to life in prison for starting a fire in March,1985 that killed his family. Prosecutors say he used gasoline to start the fire, but tests conducted four years ago proved otherwise.

The lawsuit, filed Monday in federal court, says the defendants conspired to create a false case against Gavitt, 56, who now lives in Portage.

"He didn't do anything wrong,'' attorney J. Paul Janes said. "The government convicted him of a crime that didn't occur, and put him away for 26 years in prison and threw away the key.''

Fire investigators suspected arson because of burn patterns inside the house. A State Police crime lab test on carpet samples showed traces of gasoline, but subsequent tests done on behalf of the Innocence Clinic proved otherwise, Janes said.

Gavitt, 26 at the time, suffered burns and severe cuts to his arm and burns trying to save his family from the March 9, 1985 fire at 515 N. Johnson Street in Ionia. His wife Angela and his 3-year-old and 11-month-old daughters were found dead in the girls' bedroom.

Friday marks the two-year anniversary of Gavitt's release from prison based on efforts by the Innocence Clinic at the University of Michigan Law School.

Gavitt is having a hard time adjusting to life outside of prison, Janes said, noting his client didn't receive transitional services afforded prisoners released on parole. "They just said 'there's the door, you're on your own,''' he said. "It's terrible.''

The suit alleges that a state police fire marshal wrongly concluded Gavitt was an arsonist, even though there was no evidence of financial motive, eyewitness testimony or known criminal behavior.

Errors like what happened in Gavitt's case are not isolated, Janes said. The state police in 1981 conceded fire debris samples were being contaminated when investigators put the samples in plastic butter containers. And in 1985, vapors from liquid toner in a new office copy machine was found to be skewing test results, he said.

The lawsuit, filed in U.S. District Court, is one of two filed this year against arson investigators.

A Cadillac man convicted of burning down his house in 2008 spent six years in prison before he was freed in January. He's suing the state for withholding evidence.

"David stayed in prison for 26 years,'' Janes said. "It doesn't stop. Once they knew there was a problem in their system they had an obligation to disclose it to David and his attorneys. They never did. He proved his innocence, now we need to figure out why the system got it wrong.''