One of Robinson's friends said the teen had taken psychoactive mushrooms before the altercation that led to his death, The Guardian reported.
The drugs may help explain Robinson's erratic behavior, which resulted in several people — including one of his roommates — calling the police.
The Dane County Medical Examiner's Office released a preliminary autopsy which determined Tony Robinson was shot in the head, torso, and upper body.
Additional testing and toxicology reports are underway. Results are expected in several weeks.
University of Wisconsin-Madison and local high school students staged a walkout and marched to the state Capitol.
Brandi Grayson, a member of the Young, Black, and Gifted coalition, told BuzzFeed News approximately 1,000 students marched to the state Capitol demanding to speak with the mayor.
"They're demanding justice," she said. "They're demanding answers. We don't want the same narrative we've been hearing with these stories."
Grayson said a state-wide protests is scheduled for Wednesday and that she expects at least 2,000 people to attend. Grayson said the crowds have now dispersed with many of the students returning by bus to their schools.
"When movements and change happen, they always start with the youth," Grayson said.
As protesters continued their demonstrations for the third day, audio from the police scanner was released. The tape starts with reports of a man on Williamson Street "yelling and jumping in front of cars."
The dispatcher told responding officers that the man's name is Tony Robinson and that callers said he tried to strangle someone inside the house. The dispatcher also said the callers did not report seeing any weapons. An officer responded to the dispatcher, saying he is going in to the house. Less than 20 seconds later, there is a call for shots fired.
Authorities declined to provide details on what happened in the 18 seconds from when officer Kenny entered the apartment to when the shots were fired, other than to say the two men struggled.
The fatal shooting of a 19-year-old black man by a police officer in Madison, Wisconsin, was a "tragedy beyond description," the city's mayor said Saturday.
Tony Robinson was shot Friday after officers responded to reports of a man "jumping in and out of traffic, dodging cars and the like," Madison Police Chief Mike Koval said during a news conference. Police also received a report that Robinson had been involved in a battery.
When the first officer arrived at an apartment the suspect had entered, he heard what "sounded like a disturbance coming from within the home," Koval said. The officer then forced his way into the apartment, Koval said, where the teen assaulted the officer.
Koval said Friday the officer shot and killed the teen in the "context" of "mutual combat." However, Koval confirmed Saturday that Robinson did not have a weapon.
"He was unarmed," Koval told the Wisconsin State Journal, adding that will "make this all the more complicated."
Investigators did not immediately respond to BuzzFeed News' requests for comment Saturday.
A photo posted to Facebook showed Robinson graduating from high school.
The photo, posted by Michael Johnson of the Boys and Girls Clubs of Dane County, showed Robinson at the time of his graduation from Sun Prairie High School.
Police Saturday identified the officer who shot Robinson as Matt Kenny, a 12-year veteran of the department.
Kenny has been placed on administrative leave during the investigation into the shooting, according to the Wisconsin State Journal.
According to Koval, the officer — who would later be identified as Kenny — performed CPR after the shooting but Robinson later died at a hospital.
Kenny suffered an injury to his head that was treated at a local hospital.
In a statement Saturday, Mayor Paul Soglin said there were still many unanswered questions.
"Our community has many questions, questions that I share. There will be answers," he said in a statement. "Investigators from the Wisconsin Department of Criminal Investigation were on the scene immediately last night. We must give them time to do their job."
Soglin said he had met with Robinson's family, as well as with police officers.
"Last night, at the scene of the shooting, I said this is a tragedy beyond description," he said. "Today, we begin what will be a difficult period for our City. Madisonians honor and respect the young life of Anthony Robinson. I say this without knowledge of the indispensable facts of what happened Friday night but out of respect for the dignity of every person."
Soglin said a new state law requires an independent investigation into any shooting involving a police officer.
State Rep. Chris Taylor was at the gas station across the street from the incident.
Robinson's family asked that protesters remain peaceful after the shooting, Johnson also said on his Facebook page.
"The family has asked for peaceful protest. The mother has asked that her son not be dehumanized by local authorities," he said.