Law enforcement officials in Nevada and South Lake Tahoe expanded their search Thursday for a missing Petaluma woman and announced they are examining activity on her cellphone that came later than the last known use.
Alyssa Byrne, 19, vanished early this week while in South Lake Tahoe for a three-day music festival.
In a press conference Thursday evening, Douglas County Undersheriff Paul Howell said a "ping," some kind of activity, on her cellphone was recorded at 12:03 a.m. on Jan. 1.
It hadn't been determined if the activity — which came 10 minutes after the last known use of her phone — was a text or a phone call.
"Since that time the phone has gone inactive," Howell said.
He cautioned that activity on her phone wouldn't necessarily pinpoint her location — just her phone's.
The Air Force Rescue Coordination Center at Tyndall air base in Florida is examining the cell activity, Howell said.
The FBI and search and rescue officials from Nevada and California also joined the search, as have those from the National Center For Missing and Exploited Children.
Howell said authorities were doing a "room-to-room search" of the Horizon Casino Resort, where Byrne and her friends were staying.
Security officers at the Horizon and other casino are going through their security footage, Howell said. No other sitings have surfaced.
Concerns for Byrne's safety were mounting Thursday amid a sense that something wasn't right with her in the hours before she disappeared.
Friends who saw her shortly before she went missing said she wasn't acting quite herself when she unexpectedly left a New Year's Eve concert an hour before midnight and, later, passed on a chance to visit with old high school friends at her hotel in the wee hours of New Year's Day.
The last friend to see her, Micah Alex of Petaluma, said it was his impression that Byrne was altered by alcohol or drugs when they embraced and greeted in a ground-floor passage near the lobby of the Horizon Casino Resort.
"She just seemed like something was wrong with her," Alex said Thursday, "like she wasn't all there, you know?"
But no one foresaw days of waiting and worrying as law enforcement got involved in the effort to find the missing woman and leads proved scarce.
"We're all really scared," Alex said Thursday morning.
Douglas County Nevada sheriff's Sgt. Pat Brooks said people go missing at Tahoe often, without so much ado, but single-digit temperatures made it imperative Byrne be found, he said.
Investigators said they had no leads as of Thursday evening.
A $1,000 reward was being offered in hopes someone would come forward with information, even confidentially.
"There's a lot of snow up at Lake Tahoe. The weather is cold," Brooks said. "We need to know if Alyssa's fine or not. We need to find her."
Byrne, a 2011 Casa Grande graduate, lives with her parents, Kevin Byrne and Kimberly Miller-Byrne, in Petaluma. She works as a hostess at the Cattlemens restaurant and attends Santa Rosa Junior College. Her plan is to become a paramedic-firefighter, her mother said.
Last Saturday, she and friend Jay Donnellan, a high school classmate, and two other friends from Napa drove to South Lake Tahoe for the outdoor SnowGlobe Music Festival, a three-day event on the Lake Tahoe Community College Campus that began at 3:30 p.m. Saturday.