An investigative reporter for The Las Vegas Review-Journal was found stabbed to death outside his home on Saturday morning, prompting a search for the attacker, according to the newspaper and the authorities.

The police believe Jeff German, 69, was in an altercation with someone on Friday that resulted in the stabbing, The Review-Journal reported. Dori Koren, a spokesman for the Las Vegas Metropolitan Police Department, told the newspaper that the police had potential leads on an assailant.

A motive was not immediately clear. The police department did not immediately respond to an email seeking comment on Sunday.

Glenn Cook, The Review-Journal’s executive editor, told the paper that Mr. German had not communicated any concerns for his safety or any threats made against him.

“There are no words for a loss like this,” Mr. Cook wrote on Twitter.

Mr. German’s career spanned more than three decades in the city, where he won several awards and broke stories on organized crime, casinos and political corruption.

His colleagues expressed shock on Sunday and remembered him as a superb reporter and friend.

Keith Moyer, the publisher and editor of The Review-Journal, described Mr. German on Twitter as a “reportorial force.”

“I’m still numb and profoundly sad this morning over the killing of our friend and colleague,” he wrote.

Gov. Steve Sisolak of Nevada said in a statement that Mr. German “was tough but fair and a great mentor to young reporters.”