Four people and a dog were stabbed during a break-in at their suburban Chicago home early Wednesday and three suspects are in custody, police said.

A 47-year-old man remains hospitalized, but the other three victims -- a 16-year-old girl and two males -- have been treated and released, Buffalo Grove police said. A fifth person in the home wasn't harmed, authorities said.

Police believe the incident was not random and are investigating the motive and relationships between the victims and the suspects, Buffalo Grove Police Chief Steven Casstevens said during a Wednesday morning news conference.

Police arrived to find two people outside the home with stab wounds and the front door forced in along with several broken windows, Casstevens said.

The 47-year-old man was able to grab a handgun during the attack and fired shots at the offenders, who then fled, Casstevens said. About two hours later, police in nearby Wheeling responded to a report of suspicious people at a gas station. Wheeling police determined they were the suspects and arrested them, police said. One of the suspects had blood on his pants and a bloody hunting knife, police said.