Prosecutors have claimed that he targeted the congresswoman while she was at the podium, calling for the abolition of the Immigration and Customs Enforcement (ICE) agency.
Elleshia Anne Seymour, 35, was arrested in Croatia, the Salt Lake County District Attorney's Office confirmed on Monday, nearly two months after she disappeared with her children.
Trump's call with the Minnesota Governor came after he spent the previous night blaming what he called "Democrat ensued chaos" for the killing of Pretti.
The protester who was killed, Alex Pretti, 37, had a loaded handgun on him during the deadly encounter with federal agents and held a valid concealed-carry permit, officials said.
Questions have been raised further after a doctor who saw the aftermath from his nearby apartment said in an affidavit that agents delayed giving lifesaving aid.
Pretti remained on his hands and knees for several seconds before an agent in a gray jacket appeared to take hold of his gun, moments before the fatal shots were fired.
Pretti, an intensive care nurse with the Veterans Affairs department, was remembered by his devastated family as a kind, compassionate, and deeply caring person.
The Department of Homeland Security (DHS) said that the man took out his gun and threatened Fed agents while they were attempting to arrest an illegal criminal.