A man arrested Thursday night after a series of carjackings on the Near North Side is believed to have shot his brother in Austin before heading downtown.

The carjacking and shooting spree ended with the man’s arrest about 6:30 p.m. in the lobby of a Gold Coast condo building after he stole four vehicles at gunpoint — including one from an officer — and tried to steal two more, shooting two people in the process, police said.

Before the spree, the man, who has not been charged, is believed to have shot his 23-year-old brother in the arm and chest about 4 p.m. at an apartment in the 5500 block of West Adams, Chicago Police said Friday.

Less than a half hour after shooting his brother, the man hijacked a red Jeep Patriot at gunpoint in the 5200 block of West Jackson, police said. He drove the Jeep to the 1100 block of North Milwaukee, where he hijacked a silver Jaguar about 5:15 p.m.

About 10 minutes later, the man crashed the Jaguar into several parked vehicles in 800 block of North Halsted, but continued to drive and again crashed into multiple parked vehicles in the 500 block of West Chicago, according to police.

Moments after crashing for the second time, the man got out of the Jaguar and stole a black Ford Escape at gunpoint from an undercover Chicago Police officer in the 800 block of North Hudson, police said. He drove the Ford to the 1000 block of North State, where he abandoned the vehicle.

The on-duty undercover officer wasn’t hurt.

When the suspect tried to carjack a 37-year-old man’s black Nissan in the first block of East State, the man refused and the suspect shot him in the right shoulder, police said. Then he ran to the 1000 block of North Rush, where he stole a black Jeep Patriot at gunpoint and drove it to the 1400 block of North Lake Shore Drive.

He met resistance again when an 84-year-old man refused to give up his Mercedes, police said. The 84-year-old suffered a graze wound to his left shoulder and the suspect ran into the lobby of the building and was taken into custody by officers. A weapon was recovered.

Both people who were shot during the attempted carjackings were taken to Northwestern Memorial Hospital, police said. His brother was taken to Mount Sinai Hospital, where his condition had stabilized.

“I take this very personal,” Chicago Police Chief Kevin Ryan said in a media briefing after the spree. “We are not going to let people come down here and do this.”

The suspect was taken to Area Central headquarters for questioning, but has not been charged as of Friday night.

Ald. Michele Smith (43rd) praised the police response in a newsletter to her constituents Friday.

“We are grateful for the excellent police work in apprehending this offender and seizing his weapon,” Smith said.

Smith added that Mayor Rahm Emanuel has formed a task force to combat carjackings in the city, but said more was needed.

“Inadequate laws and lax handling of repeat offenders are emboldening robbers and carjackers to commit these brazen crimes,” Smith said in the newsletter.