(WPXI) – Homicide charges have been filed four years after the disappearance of Cassandra Gross. Thomas Stanko, who was Gross’ estranged boyfriend, is facing several charges including criminal homicide, tampering with evidence and abuse of a corpse. Stanko was a person of interest in the case but was never criminally linked to her disappearance until now. Gross went missing on April 7, 2018 and was never found. A judge declared her legally dead from a homicide about nine months later. In July this year, Stanko was sentenced to seven years in prison for illegally possessing guns. He is a convicted felon, meaning he isn’t allowed to own or carry any guns. Investigators found 17 guns inside his properties in Unity Township when they were searching for evidence in the disappearance of Gross. Three of the guns were stolen property.