Evening mass at the Cathedral of St. Paul had just ended Wednesday when maintenance worker Nathan Leonhardt headed to the church's north side to begin locking up.

He pushed open an inside door that led to a small stairwell and exterior doors along Dayton Avenue, and it smacked against a green plastic laundry basket at the top of the stairs.

Leonhardt peeked inside to see a green, Ninja Turtles fleece blanket, white socks and a dark-colored women's zip-up hoodie. "Didn't really think anything of it," he recalled Thursday.

Leonhardt locked the exterior doors and was about to re-enter the church, thinking the basket's owner was inside waiting to claim it. But he decided to feel inside the perimeter of the round basket. Nothing.

He'd come back to see if the basket was still there after locking the other doors, he thought.

Leonhardt was about to leave when he heard it — a small cry. He froze. Was it a baby? A puppy? He pinched himself to make sure he wasn't dreaming. A puppy, Leonhardt decided.

But when he peeled back the blanket, he found a naked, newborn boy still wet with blood and afterbirth. A binder clip squeezed off the umbilical cord. There was no clue as to who he was or who had left him there.

"I was in shock," Leonhardt said during a news conference Thursday. "It's a scenario that's never going to leave my head for the rest of my life."

Leonhardt gathered up the boy, grabbed the blanket and wiped off the afterbirth. It was reflexive — the 26-year-old South St. Paul resident has a 4-year-old daughter, and said it was as if he was back in the delivery room.

"It felt like it was mine," Leonhardt said of the boy, "like he was my own child."

The nameless boy left at one of Minnesota's most iconic houses of worship would leave that impression on everyone who came to his aid.

The cathedral's rector, Rev. John Ubel, baptized the boy right there, naming him Nathan John after his rescuers.

Ubel then lay awake in bed that night worrying about the infant — despite being told that he was in good condition.

When sleep did come, the boy filled Ubel's dreams and spoke to him.

"As you might imagine," Ubel said at the news conference, "a lot of things happen at the cathedral. It's never a dull day, but we both agree that this was the most amazing day since both of us have been here at the cathedral.

"It was just a pretty profound moment for both of us."

The St. Paul police officers who responded to the scene later pooled their money to buy the boy a monkey hat, booties, a bouncy chair, a blanket, onesies, a Sophie the Giraffe toy and a swaddle blanket.

Sgt. Charlie Anderson, who was supervising the Western District, and two other officers delivered the presents to Children's Hospital, where medics had taken the boy.

"We got to cuddle around the incubator where the baby was," Anderson said.

"He was snug as a bug. We had some group hugs with the nurses, and everybody had some wet eyes.

"We want to let the mother know that her son was surrounded by people who instantly fell in love with him, and that we wish the best for her and the baby."

But the situation wasn't always so upbeat. Leonhardt said the stairwell was chilly when he found the boy, whose fingers and toes were starting to turn purple.

The outside air temperature at 6 p.m. in St. Paul was 2 degrees with a 13-below windchill, according to the National Weather Service Office in Chanhassen.

Anderson, a father of three children younger than 8, knew the boy needed immediate medical attention when he arrived at the scene.

"I could tell right away that the medics needed to step it up," Anderson said.

"The baby had lost a little bit of coloring, and we didn't know — with loss of body heat and a child that age, things can be irreversible very quickly."

Anderson said he believed the baby was "brand-new, [born] within an hour or so."

Rev. Ubel said that the baby was very quiet, aside from a small cry he let out when a cold wind swept in as he and Leonhardt took him into the sacristy.

" 'Don't worry, it's OK,' " Ubel said he told the baby in that moment.

" 'Welcome to Minnesota. Get used to it. This is life here in the winter.' "

He couldn't recall a similar incident in his career.

"Suffice it to say, in more than 27 years as a priest, I've never witnessed anything like this," Ubel said. "Honestly, I was very nervous."

Sgt. Mike Ernster, a police spokesman, said that the baby was in good condition Thursday and that the case had been turned over to Ramsey County Child Protection.

Authorities are not treating the case as a criminal matter, nor are they looking for the boy's parents even though a Minnesota law that allows mothers to give up their newborns does not sanction churches for those circumstances.

Minnesota's Safe Place for Newborns law was first enacted in 2000 and amended in 2012 to allow mothers to give up newborns to hospitals and urgent care clinics or by calling 911 for an ambulance.

Wednesday's incident does not qualify as a "safe place" case since it involved a church, the Minnesota Department of Human Services, or DHS, said in a written statement.

It's unknown if any babies have been given up so far this year under the law.

According to DHS, under the law, three infants were given up in Minnesota in 2016 as of Dec. 20, 10 infants were given up in 2015 and six in 2014. Three infants were "saved" rather than surrendered to a sanctioned location in 2013, DHS said.

The babies were relinquished in Beltrami, Hennepin, Le Sueur, Pennington, Ramsey, St. Louis and Stearns counties. DHS said there is no known case of a mother reclaiming a child.

DHS Commissioner Emily Piper attended Thursday's news conference with Leonhardt and Ubel, and said mothers should feel "no blame, no shame" in taking advantage of the safe place law.

Mothers will not be asked any questions about surrendering their child, she said, adding that law enforcement have been thoughtful about not criminalizing them.

"I just cannot imagine the pain that mother feels and the difficulty in the decision" to leave the boy at the cathedral, Piper said. "I hope she has peace with the decision that she made."

Piper urged anyone whose interest in adoption was piqued by the boy's story to consider the hundreds of other children in Minnesota in need of homes.

"We have almost 500 other children out there waiting for a loving family to ask for them," she said.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib