KANSAS CITY, Mo. — After nearly a month of reports of gunshots being fired at vehicles and more than 100 tips, authorities announced charges Friday against a Kansas City-area man suspected in about a dozen highway shootings that wounded three people.

Jackson County prosecutor Jean Peters Baker said at a news conference that 27-year-old Mohammed Whitaker of Grandview was charged with 18 felony counts and is being held on $1 million cash bail. Baker said Whitaker, who had been under surveillance by police for about a week before his arrest, was charged with two counts of shooting into a motor vehicle and injuring a person, seven counts of shooting into a motor vehicle and nine counts of armed criminal action.

“This has impacted all of us, each side of State Line, each side of the river,” Baker said. “It’s been something that’s been at the hearts and thoughts of all of us since the day this case first broke.”

Police Chief Darryl Forte declined to discuss a possible motive for the shootings, and the probable cause affidavit released Friday does not address the issue.

Whitaker’s mother, Maria Dunn, 55, said she doesn’t believe any of the charges against her son, who she said has always been “happy” and a “good kid.”

“Right now, there’s so many things in my head. … All I know is that I can’t believe this is happening to him. I just can’t,” Dunn said from her home in Texas. She said the family lived in central Missouri for a while and that her son attended high school in Huntsville before he moved to Kansas City to attend DeVry University.

A reward of up to $10,000 was offered for information leading to an arrest.