The police open an investigation and determine that Anya's fingerprints on the bottle and glass were indeed planted. Lisa is placed under arrest based on a statement from Mrs. Roper, who had seen her handle the items shortly after Anya's death and had also seen her and Karl embrace.
After discovering that Anya's fingerprints were found on the bottle and glass, the police arrested Lisa. This was due to Mrs. Roper's testimony, which stated she saw Lisa handle the items shortly after Anya's death and witnessed her embrace with Karl.