Investigators found what they believe is blood evidence inside the car of a missing Maine mother, a police source confirms to FoxNews.com.
The discovery was made as police investigate the disappearance of 20-year-old Krista Dittmeyer, whose car was found abandoned in a New Hampshire parking lot with her baby daughter inside.
Authorities said Dittmeyer -- who lives in Portland, Maine, and is considered missing and endangered -- last talked to family members by phone at around 8 p.m. Friday.
Police received a call from a passerby at around 6:30 a.m. Saturday who reported Dittmeyer's car in the Cranmore Mountain resort parking lot in Conway, N.H., with its hazard lights blinking and door slightly ajar. The young woman's 14-month-old daughter was unharmed in the backseat, but Dittmeyer was nowhere to be found.
Conway Police Lt. Christopher Perley told FoxNews.com he does not believe Dittmeyer left her car willingly.
"From a very early point in the investigation we drew the conclusion that she did not voluntarily absent herself from her car," he said during an interview.
Perley said police have obtained warrants to search two vehicles -- one being Dittmeyer's black Nissan Sentra -- for clues in the case. He would not elaborate on the second vehicle being investigated. He also would not confirm whether blood was found in the vehicle, saying the Conway Police Department "does not comment on specific pieces of evidence."
Perley said police don't know why Dittmeyer drove to Conway, but noted that the young woman had a "number of social contacts" in the area.
The woman's sister, Kayla Dittmeyer, told the Portland Press Herald that she believes someone forced her sister out of the car and that her sister persuaded that person to leave her daughter behind.
"My sister is very headstrong, but she is also very bold and very honest. That is why I feel she is OK. She's a very strong person," Dittmeyer said of her sister, a single mother who works as a waitress. "I believe she is trying to talk her way through this."
"She would do anything for her," she said. "It was all so out of character for her. She would never put her daughter in harm's way."
Dittmeyer's family is offering a $3,000 reward for help finding her. A vigil is also being planned for Thursday in Bridgton, Maine, where Dittmeyer's family lives.
Anyone with information on Dittmeyer's whereabouts is being urged to call the Conway Police Department at (603) 356-5715.
Cristina Corbin is a Fox News reporter based in New York. Follow her on Twitter @CristinaCorbin.