Sussex Police have a arrested a man on suspicion of assault after the incident, in Shelley Road, at 3.15pm yesterday afternoon (November 22).
The police were at the scene for more than four hours.
A police spokesperson said: “At 7.35pm officers entered the flat and safely arrested the 59-year-old man on suspicion of assault.
“He is currently in custody for interview and further enquiries.”
Officers had been called following concerns for a man’s welfare, a spokesman for the force said.
A police dog unit was also pictured at the scene, along with crews from the ambulance service.
The police said they secured the area to ensure public safety and that nobody was injured.