A woman and her dog were brutally stabbed to death early Wednesday at Atlanta’s Piedmont Park in what police described as a “gruesome” scene.

Katherine Janness, 40, was found dead at the park around 1 a.m., along with her slain dog Bowie. Police said that Janness had been stabbed multiple times.

Janess’ parter of seven years Emma Clark said that Janness went to walk Bowie after dinner but never returned, according to the Atlanta Journal-Constitution. When she didn’t come home, Clark tracked her phone’s location and went to the park, where she discovered her girlfriend dead.

The FBI confirmed with ABC News it is now joining the Atlanta Police Department’s investigation into her death, So far, no arrests have been made in the case.

Police have shared a surveillance image showing Janness crossing a street near the park before she was found dead.

On Thursday more than 100 people attended a vigil for Janness at the park, where her partner’s father described the killer as a “monster.”

“What they did to her is ridiculous. There is a monster on the loose in the city of Atlanta,” Joe Clark said according to ABC Atlanta affiliate WSB-TV.

“It’s a gruesome scene,” deputy police Chief Charles Hampton said to the outlet on the murder.

Police have since added five mounted patrol units to the park, a popular area for locals and dog walkers. Police have combed the area this week and divers went in and out of the lake for hours Wednesday searching for potential evidence.

A $10,000 reward is being offered for information that could help lead to an arrest.

If you can help, please call the Atlanta Police Homicide Unit or Crime Stoppers at 404-577-8477.