A St. Paul man was charged with second-degree attempted murder and assault Friday, accused of pouring a deadly poison on his ex-wife during a custody visit in a Roseville park.

According to the complaint, filed in Ramsey County District Court, Thorbjorn Vandis Koyen MacBain, 38, assaulted his ex-wife Wednesday in front of their two children at Central Park in Roseville. The woman remained at the park during the visit because she did not trust MacBain to return the children to her.

MacBain and the children played with squirt guns while she sat on a park bench. MacBain went to the bathroom and returned with a bottle of liquid that he poured on his ex-wife.

She said the liquid had a smell and didn't taste or feel like water. Immediately after the liquid was poured on her, she thought she was going to lose consciousness and could not stand up.

MacBain tried to leave the park but could not because the children had hidden his backpack. The victim called 911 but was unable to speak.

When MacBain called 911, he said she was having a panic attack, and he had an unusually extensive knowledge of her medical history even though they had been divorced for seven years, the charges say.

She was taken by ambulance to Regions Hospital in St. Paul, where her condition deteriorated, the charges say. She was treated by toxicology specialist Dr. Robert Pueringer, who said that she nearly died. He told police that all of her symptoms were consistent with poisoning with an organophosphate, which includes pesticides and nerve agents sarin, sabun and soman.

One of the children was also splashed with the poison, but the child's symptoms were much less severe.

One child told police that MacBain was not concerned about their mother's condition before he called 911, but then sounded concerned while on the phone with 911. After the call ended, he went back to being unconcerned, the child said.

He was arrested Thursday outside his girlfriend's home.

MacBain, whose former legal name was Trevor Alexander Bain, is being held in lieu of $1 million bail.

Friday afternoon and evening, the FBI's Hazardous Evidence Response Team and other law enforcement personnel searched the suspect's home in the 600 block of Asbury Street in St. Paul as part of the investigation, authorities said.

"The purpose of the FBI activity in the home in question today was to recover any and all evidence of any potentially dangerous material," the FBI said in a news release. "Once collected and secured, evidence will be delivered to the FBI lab in Quantico, Virginia, for testing in furtherance of the Roseville PD's ongoing investigation."

Zoë Jackson covers young and new voters at the Star Tribune through the Report For America program, supported by the Minneapolis Foundation. 612-673-7112 • @zoemjack