FBI evidence technicians mark spots at the third-base dugout during the aftermath of the shooting at a congressional baseball practice in Alexandria on June 14, 2017. (John McDonnell/The Washington Post)

The Illinois man who in June opened fire on Republican members of Congress at a baseball practice in Alexandria had "cased the field" for weeks and was spotted watching the lawmakers play the day before the shooting rampage, according to a new report issued Friday.

Authorities said they believe James T. Hodgkinson selected Eugene Simpson Stadium Park as a target as early as April, when he took pictures of the field, which were later found on his phone. That was shortly after he had driven to Alexandria in a white Ford conversion van, which he lived out of for months.

The details are among those contained in a 41-page report by Alexandria Commonwealth's Attorney Bryan L. Porter, who concluded that U.S. Capitol and Alexandria police officers were "legally justified" in fatally shooting Hodgkinson after the gunman had wounded four people, including House Majority Whip Steve Scalise, and engaged officers in an intense gun battle.

The report says Hodgkinson fired 62 rounds from the assault-style rifle — 33 near third base, where he had started his attack, and an additional 29 near home plate. Officers fired at least 40 rounds at Hodgkinson, striking him three times. The incident lasted nine minutes.

[Police say gunman cased field before shooting spree on Congressional baseball practice]

Hodgkinson, a 66-year-old unemployed home inspector, had been angry with President Trump, and police have said he deliberately targeted Republicans the morning of June 14. He used a Century Arms International SKS semiautomatic rifle and a Smith & Wesson 9mm handgun, authorities said. He had no criminal record, and the guns were purchased legally in Illinois.

Scalise was shot in the hip and gravely wounded as he fielded balls at second base, but he recovered. The Louisiana Republican, who turned 52 on Friday, returned to the House for the first time on Sept. 28, where he was received with applause and tears.

"I'm definitely a living example that miracles really do happen," Scalise said.

[Gunman from Illinois opens fire on Republican lawmakers]

Others injured included Matthew Mika, a lobbyist struck in the chest, and Zachary W. Barth, who worked for a Texas congressman and was shot in the lower left leg.

The report credits Scalise's security detail — Capitol Police agents Crystal Griner, who was wounded in the leg early in the shootout, and David Bailey — with pinning down Hodgkinson with gunfire moments after he started shooting. Bailey, the report says, ran onto the field amid the gunfire, an action Porter described as a "courageous act" that "helped avert disaster."

Griner and Bailey arrived at the field with Scalise about 6:20 a.m. and parked the black Chevrolet Suburban they were driving behind the first-base entrance to the field. They were in the vehicle with the windows down when the first shots were fired just after 7 a.m. Both spotted Hodgkinson at the third-base fence, the rifle barrel sticking through the chain links.

Players were shouting and running; others dropped to the field or dove into dugouts. Scalise was the first to be struck. Mika went down next and was helped off the field. Barth, who was in center field, ran to the warning track but could not find a way out. He lay down and "sensed bullets impacting the ground around him," the report says. He was shot in the leg and ran to the first-base dugout.

Bailey saw Scalise fall and tried to run to him but was met by gunfire. The report says he heard "bullets go past his head." Standing by the first-base dugout, Bailey returned fire with his Glock pistol.

[Injured congressman returns to chamber amid applause]

The report says Hodgkinson appeared to lose focus and fired more erratically. He also moved, making his way behind home plate to a blue cinder-block storage shed.

Griner was still at the Chevrolet Suburban, taking cover behind the front driver-side door. Bailey returned to the vehicle to reload as Griner continued to shoot. One bullet struck Griner in the left ankle. She could no longer stand, though the report says she continued to fire as she lay under the Suburban.

Meanwhile, police officers from Alexandria were speeding toward the ballpark, among them Kevin Jobe, Alexander Jensen and Nicole Battaglia. Jobe saw Bailey shooting toward the shed. Battaglia drew her weapon and ran toward the building. The gunman approached her and fired a burst of five to six rounds, the report says, striking a Lexus she was hiding behind.

Jensen, on the force just two years and an hour short of the end of his midnight shift, retrieved a Bushmaster semiautomatic rifle from his cruiser. His first shot missed. His second struck Hodgkinson in the right hip, causing him to fall and drop his rifle. The report says Hodgkinson took his 9mm gun from a holster and began shooting.

The report says Jobe advanced toward Hodgkinson as he fired and yelled to the gunman to "get down." The report says that one of Bailey's shots struck the gunman in the chest. Hodgkinson pivoted as Jensen, standing next to his cruiser 200 feet away, took another shot with his .223 caliber Bushmaster, striking Hodgkinson in the left hip and putting him to the ground a final time.

He died later at a hospital.

Rachel Weiner contributed to this report.