DNA from Las Vegas elected official Rob Telles was found at the scene of the fatal stabbing of investigative journalist Jeff German, police say.
Mr Telles, a Clark County public administrator, was arrested on Wednesday after a Swat team descended on his Las Vegas home.
Captain Dori Koren said that DNA recovered from the murder scene had been matched to Mr Telles.
Mr Koren added that a pair of bloodied sneakers and a distinctive straw hat that matched those of the suspect captured on video were found at Mr Telles’ home.
The shoes and the hat had been cut up in an attempt to destroy evidence, he added.
His family released a statement to say they are “shocked, saddened and angry” about his death.
“We’re shocked, saddened and angry about his death,” the statement, released to the Las Vegas Review-Journal, where German worked, said.
“Jeff was committed to seeking justice for others and would appreciate the hard work by local police and journalists in pursuing his killer.”
Mr Telles was booked into the Clark County Detention Center on Wednesday night after being treated for self-inflicted injuries at a hospital.
Officials described the injuries as non life-threatening.
Clark County Sheriff Joe Lombardo told reporters it had been “an unusual case from the beginning”.
“This is a terrible and jarring homicide,” Mr Lombardo said.
“One that has deeply impacted Las Vegas. Every murder is a tragic, but the killing of a journalist is particularly troublesome.”
The 69-year-old journalist was found dead outside his home in the city on 3 September, with investigators believing he was fatally stabbed in an altercation the day before.
German had spent the last few months reporting on Mr Telles, a Democrat who failed in his bid for re-election in June’s primary after the newspaper published a series of stories about him.