The staggering toll in the deadliest mass shooting in US history has climbed to 58 killed and more than 500 injured, a law enforcement official said — adding that the suspected shooter killed himself after the rampage.

Stephen Paddock, 64, of Mesquite, Nev., shot himself in his Mandalay Bay hotel room on the 32nd floor, where he had been staying since Thursday, Clark County Sheriff Joseph Lombardo said.

“We believe the individual killed himself prior to our entry,” Lombardo said.

Police found a cache of 10 rifles in his room, Lombardo said, adding that it was unclear how he managed to keep the weapons from being discovered by housekeeping staff.

Cops were able to locate the room due to its smoke detector, which was blaring as a result of the heavy smoke created from the automatic weapon, a former Las Vegas police officer told CBS News.

“The way the shooter was identified was not from the muzzle flashes, but the smoke detector in the room went off from the amount of smoke that came from firing that fully automatic weapon,” said the officer, Randy Sutton.

Meanwhile, the woman who had been sought in connection with the shooting has been cleared, the Las Vegas Review-Journal reported.

“Marilou Danley is no longer being sought out as a person of interest,” Las Vegas police said of the 62-year-old woman, who has been living with Paddock in a retirement community.

“LVMPD detectives have made contact with her and do not believe she is involved with the shooting on the strip,” police said in a statement.

Authorities are continuing to look for a Hyundai Tucson with Nevada license plate 114 B40, the paper reported.

At least 406 people were taken to hospitals after the massacre, Lombardo said in a morning press briefing.

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Among the killed was an off-duty Las Vegas police officer, whose name was not immediately released.

Two on-duty officers also were hurt. One of those has been upgraded from critical to stable condition, officials said.

The Los Angeles Sheriff’s Department said two of its off-duty members also were wounded. One was in critical condition and the other in stable condition.

Their names have not yet been released.

The US Homeland Security Department says there is no “specific credible threat” involving other public venues across the country.

Police have not yet determined a motive in the shootings.

Heavily armed officers were searching a Nevada retirement-community home where Paddock had been living in Mesquite, a city about 80 miles northeast of Las Vegas.

Mesquite Police Chief Troy Tanner said police surrounded and entered the single-family home where Paddock lived with Danley.

Police saw “no movement” inside the house before serving a search warrant at the one-story, three-bedroom home in the Sun City Mesquite retirement community.

Detectives from Las Vegas and North Las Vegas were at the scene in the community, located near the Arizona state line, Tanner added.

Las Vegas Mayor Carolyn Goodman asked for prayers for her grieving city.

“Thank you to all our first responders out there now,” she tweeted.

Nevada Gov. Brian Sandoval also released a statement on Twitter that a “tragic & heinous act of violence has shaken the #Nevada family” and offered prayers to those affected by “this act of cowardice.”

Pope Francis called the shooting a “senseless tragedy” and offered his prayers for victims.

The Vatican secretary of state has sent a telegram of condolences to the bishop of Las Vegas, saying the pope was “deeply saddened” to learn of the shooting.

With Post wires