Police investigate the scene of a double murder that left two brothers dead with gunshot wounds in the 1700 block of Park Avenue West in Highland Park. | Photo: Craig / Captured News

Police have identified the man who allegedly shot both of his brothers to death and then set a house on fire in Highland Park before fleeing the scene earlier this week.

Jeffrey S. Austwick, 54, of the 1700 block of Park Avenue West in Highland Park, was arrested in St. Louis, Missouri after police issued a warrant for him in the double murder case, Lake County Major Crime Task Force Spokesman Christopher Covelli said Friday evening.

Two brothers – 63-year-old Marc Austwick of Lake Forest and 60-year-old John Austwick of Mundelein – were found shot to death outside of a burning house in the 1700 block of Park Avenue West early Wednesday morning.

A preliminary investigation shows that Marc and John went to the house to discuss the property with Jeffrey, Covelli said.

Police investigate the scene of a double murder that left two brothers dead with gunshot wounds in the 1700 block of Park Avenue West in Highland Park. | Photo: Craig / Captured News

“The property was owned by the mother of the three, and she recently passed away,” Covelli said.

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After the two brothers arrived, Jeffrey allegedly shot them and then set the house on fire.

Jeffrey then fled the scene in his vehicle, Covelli said.

Investigators obtained a nationwide arrest warrant for Jeffrey later on Wednesday for two counts of murder.

Police gather Wednesday morning at the scene of a double murder in the 1700 block of Park Avenue West in Highland Park. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

At around 5:30 a.m. Friday, local police arrested Jeffrey at a park in St. Louis, Missouri.

He remains in custody in Missouri pending an initial court hearing, Covelli said.

The Highland Park Police Department and Highland Park Fire Department responded to the home at around 3:50 a.m. Wednesday after a neighbor reported the house was on fire.

Firefighters arrived to find the house was heavily involved in flames.

While evaluating the fire, firefighters found the two brothers dead in the grass outside of the house.

Firefighters battle a house fire in the 1700 block of Park Avenue West in Highland Park early Wednesday morning. Two men were discovered murdered outside of the house. | Photo: Max Weingardt

The Lake County Coroner’s Office confirmed later on Wednesday that both men died from multiple gunshot wounds, not from the fire itself.

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Firefighters eventually extinguished the fire with the help of other fire departments in the area.

A crime scene was immediately established and numerous police and fire investigators, including the Illinois State Fire Marshal, responded to the scene.

Federal law enforcement, including the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the U.S. Marshals Service, joined the local investigators.

An arson dog and his handler from the Illinois State Fire Marshal investigate the scene of a house fire and double murder in the 1700 block of Park Avenue West in Highland Park. | Photo: Max Weingardt

Highland Park Police requested the Lake County Major Crime Task Force to assist in the double murder investigation.

Authorities said that the murders appeared to be isolated and there was no threat to the community.

Park Avenue West between Ridge Road and Sunnyside Avenue was shut down Wednesday and Thursday due to the investigation.

A real estate sign was seen in front of a house in the 1700 block of Park Avenue West where two brothers were allegedly murdered. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

The property where the incident occurred appeared to be for sale because a real estate sign was in front of the home.

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Lake County court records of the case were not immediately available to the public Friday evening.