() A police officer’s gut instinct to check on a lawmaker may have prevented additional deaths during a deadly shooting spree that left a Minnesota legislator and a spouse dead, authorities said Monday.

Vance Boelter, 57, faces federal and state charges in the Saturday attacks that killed state Rep. Melissa Hortman and her husband in Brooklyn Park. State Sen. John Hoffman and his wife survived critical injuries after being shot at their Champlin home earlier that morning.

The violence began around 2 a.m. Saturday, when Boelter, wearing a silicone mask and posing as a police officer, shot the Hoffmans at their front door after demanding entry. He then traveled to homes of other Democratic lawmakers, ringing doorbells and claiming to be police.

At 3:30 a.m., Brooklyn Park officers conducting welfare checks arrived at Hortman’s residence just as Boelter began his assault. The suspect immediately opened fire before entering the home and killing Hortman, her husband and their dog, then fleeing on foot.

“There’s absolutely no question that the work of those officers did stop what could have been a far worse night,” Minneapolis Police Chief Brian O’Hara said on ‘s “Elizabeth Vargas Reports.”

Court documents reveal Boelter had stalked multiple Democratic officials, using websites to obtain personal information and addresses. He researched lawmakers’ homes, purchased police equipment including fake license plates and carried notebooks containing dozens of names of elected officials and abortion rights activists.

Authorities recovered five weapons, large amounts of ammunition, tactical gear and targeting notes from Boelter’s abandoned SUV. The suspect was captured Sunday evening after a 43-hour manhunt that officials called the largest in Minnesota history.

Federal prosecutors described the attacks as political assassinations that were intended to be part of a larger killing spree targeting Democratic politicians.

‘s Stephanie Whiteside contributed to this report.