Payne spent the previous evening celebrating her birthday with friends. She was last seen around 1:30 a.m. ET on Tuesday, several blocks from the nearby riverfront. The Baltimore Police Department released an advisory notice later that evening, offering preliminary details about its investigation and requesting that anyone with information about Payne contact its missing persons unit.

Homicide detectives took over the police investigation on Wednesday, a Baltimore Police spokesperson confirmed to Newsweek. The spokesperson said individuals with knowledge of Payne’s possible whereabouts should contact the police department’s homicide division at 410-396-2100.

Investigators “have reason to believe Ms. Payne may have fallen into water” near Boston Street corridor, which police identified as the site of her disappearance, according to the department spokesperson. Baltimore Police’s marine unit searched the water on Wednesday afternoon, but Payne remained missing in the early evening.

Payne’s loved ones spread word of the woman’s disappearance on social media soon after she went missing, sharing photos and identifying physical characteristics alongside pleas to assist police in locating her.

Terry Stopowski Moritz, who referred to Payne as her niece in a Facebook post shared Tuesday, described the search as a “nightmare” and said the woman’s purse was found on Boston Street. Baltimore Police could not verify that Payne’s handbag was discovered on Wednesday, nor confirm other statements Moritz relayed on Facebook, given the ongoing nature of the department’s investigation.

“it’s a freaking nightmare; my niece Savannah Payne didn’t show up for lunch w/me today to celebrate her birthday; when I called her cell phone Baltimore Police answered,” Moritz wrote in Tuesday’s social media post, which had been shared 11,000 times by Wednesday evening.

“She has not been seen since she was out partying around Canton last night; her car was left where she parked it and her purse was found on Boston Street. If anyone was in that vicinity last night and heard or saw ANYTHING please, please contact the Baltimore police,” the post continued.

Moritz asked those who know Payne’s family personally refrain from contacting them, as “they need a little bit of space and also want to leave phone free in case the police call them.” Payne’s parents were reportedly present during the Baltimore Police marine unit’s search on Wednesday afternoon, according to WJZ-TV, the Baltimore CBS affiliate.