Authorities have new information related to the disappearance of a 19-year-old woman from a South Lake Tahoe hotel New Year's Day.

Deputies announced Thursday during a news conference in Stateline, Nev. that investigators discovered a new cellphone signal that came from Alyssa Byrne's phone before midnight Monday.

Byrne's last cellphone activity was thought to be at the SnowGlobe Music Festival New Year's Eve, but investigators have discovered an additional signal.

"We're still analyzing that data and we don't yet know if it's a phone call or a text," said Paul Howell, the Douglas County undersheriff. "It takes a while to determine that and we still don't know the exact location of its use."

Kim Byrne, Alyssa’s mother, clung to the new information that revealed a new clue from her daughter’s cell phone before it died

“They found that they got a ping after midnight,” she said. “Last I heard, it was near a soccer field, a baseball field, something like that, so at least they have a footprint where to go.”

The Petaluma woman went missing after she attended the concert in South Lake Tahoe New Year's Eve. 

The three-day music event typically draws an estimated 40,000 people and was held at the Lake Tahoe Community College campus Dec. 29-31.

Byrne was staying with friends at the Horizon Casino Resort in Stateline, Nev., Douglas County sheriff's Sgt. Pat Brooks said.

Authorities conducted a room-to-room search Thursday of the Horizon casino. Crews were also doing air and ground searches of snowbanks around the casino strip and in South Lake Tahoe.

Her friends last saw her in the hotel bar between 12:30 and 1 a.m. on New Year's Day, Douglas County sheriff's Sgt. Pat Brooks said.

Authorities said after the festival ended, Alyssa Byrne had taken a shuttle bus by herself back to the hotel, while her friends went to a New Year's street celebration in the downtown area.

When the friends returned to the hotel, they saw her in the lobby, spoke with her briefly and headed to bed while she remained in the lobby, Brooks said.

At the hotel lobby the surveillance shows the missing woman sat there for a few minutes, looked up and walked out.  

Alyssa Byrne's Twitter account showed two final tweets made Dec. 31 that suggest she was upset. One said she "Just lost trust in the person (she) trusted most." That was on the afternoon of New Year’s Eve.

The Sheriff's Department said it can't confirm if those tweets came from her and said witnesses who last saw her at the hotel said she was in good spirits.             

Kevin Byrne made a desperate plea Thursday to anyone who has information on his daughter's disappearance.

"My level of hope is that she's out there," said Kevin Byrne. "If you are, just come home. We love you. We miss you. We just want to hear any tip that's out there at this point."

Family and friends said it's very unlike her to not contact family or friends.

Law enforcement officials said their search effort has not turned up any evidence of foul play.

Alyssa graduated from high school two years ago,

She was studying to be a firefighter at Santa Rosa Junior College and worked as Cattlemen's restaurant

Co-workers described her as reliable, energetic, funny.

 “She's like ’I'm going to SnowGlobe,’ and then she just didn't come back,” said Elise Boniglio, a coworker. “It's crazy because you never think that's going to be you.”

Posters with the 19-year-old’s picture have been posted all over Petaluma, and on a larger scale a Facebook page was set up to assist in the search.

Byrne is 5 feet 3 inches tall, weighs 125 pounds and has black hair and blue eyes. She was last seen wearing a black sweatshirt, black snow boots and black yoga-type pants, Brooks said.

A reward of up to $1,000 has been offered for information leading authorities to her, Brooks said.

The sheriff's department will update the search Friday morning.

Anyone with information is asked to call the Douglas County Secret Witness phone line at (775) 782-7463, or the sheriff's office investigation division at (775) 782-9905.