Francis Gerald Grady, 50, was charged Tuesday with two federal crimes in the attack, which took place Sunday night in the town of Grand Chute. No one was injured and the explosion did only minor damage to the clinic.
Grand Chute Police Chief Greg Peterson said investigators in the case learned that Grady may have been involved in past protests at the office. The information was so far unconfirmed, Peterson said, but it is being looked at closely by the team of local and federal investigators handling the case.
"There was some indication that surfaced at some point that he has been involved in some of the demonstrations," Peterson told TPM. But the chief described the information as coming from "someone who didn't have direct knowledge," so there was still more work to be done.
The Planned Parenthood location in Grand Chute has been a regular target of anti-abortion demonstrations for years.
One of the most vocal groups to protest there is Pro-Life Wisconsin, which puts out weekly announcements asking for volunteers to organize regular demonstrations. The announcements describe the location as a place "where abortions are sold and committed."
The group held events throughout Wisconsin on Sunday for the closing of a nationwide campaign called 40 Days for Life. None of the events that day took place at the Grand Chute clinic, but one was scheduled for a Planned Parenthood clinic in the neighboring town of Appleton, according to the group's website.
On Tuesday, Steven Karlen, the development director of Pro-Life Wisconsin, told TPM that none of the organization's staffers had heard of Grady.
Karlen added he would be surprised if the suspect had been part of "any mainstream pro-life" organizations, given Grady's long criminal record.
Grady has a history of criminal convictions and run-ins with the law, including a 2004 conviction for manufacturing or distributing cocaine and a 2011 no contest plea to resisting or obstructing a police officer.
The Grand Chute police chief said if Grady does have ties to the anti-abortion demonstrations, it would be a departure from what usually takes place.
"For the most part those demonstrations are very peaceful," Peterson said. The protesters generally follow the rules and avoid blocking entrances or driveways.
But Peterson also said Grady's views on abortion are going to play a key role as the case moves into the courts.
"Motive is going to be important at some point in this process," he said. "Certainly if he's been involved in the past, it's going to help tell us why he might have done this."
Grady was scheduled to make his first appearance Wednesday in federal court in Green Bay, Wis., where he was charged with arson of a building used in interstate commerce and intentionally damaging a facility that provides reproductive health services.