THORNTON — A man suspected of starting a fire at a suburban Denver condominium complex has surrendered.

The Adams County Sheriff's Office says 20-year-old Martin (Mar-TEEN') Espinoza turned himself in Friday.

Espinoza was among the people who gathered to watch the fire Tuesday and was interviewed by a television reporter.

At the time, he told KMGH-TV (http://bit.ly/1dz3ukG) that his mother lived in the building where the fire started. He said he saw everyone run toward it and saw smoke start billowing up.

The sheriff issued an arrest warrant for Espinoza on Thursday on charges of attempted murder, arson and aggravated cruelty to animals.

Investigators are still trying to determine how the fire started.