Johnson is charged with three murders, including the death of DeLindsey Mack, a Lamar High School student who was shot close to campus last year.
The mother of one of the victims, Kenneth Roberson, was in court to see a judge raise Johnson's bond.
"He is just evil," said Yvonne Ferguson, Roberson's mother.
Prosecutors were trying to get the judge to set a no bond for Johnson. Meanwhile, his attorney was asking to set bond at a reasonable amount.
Prosecutors believe Johnson was one of the leaders of the "103" street gang in Houston's south side. They believe he instructed as many as six people to carry out the slayings, but he's charged with just three murder counts, so far.
On Wednesday, prosecutors played surveillance video that appeared to capture several of these murders as they occurred.
In the case of Mack, surveillance video from an apartment complex near the Lamar campus showed the last moments of the young man's life as two people fired shots. Prosecutor said one of them is Johnson.
Another surveillance video was shown in court of a man who was shot during a drive-by shooting. He died on the side of the street next to a parked car. Investigators say Johnson was also responsible for that murder, even though he has not been charged with that crime.
"We feel like he is an extreme danger to public safety," said prosecutor Sarah Seely. "He has committed several murders that are currently uncharged and we are still investigating."
In addition, prosecutors played a third video showing several people, including Johnson, allegedly robbing a hotel clerk at gunpoint. He is charged with aggravated assault with a deadly weapon in that case.
Besides surveillance video, prosecutors sought to use social media accounts belonging to Johnson and other gang members against him. Investigators filed search warrants on more than 80 different Instagram accounts. Investigators testified that over the past year, they estimate looking through at least a half a million Instagram messages among 103 gang members.
Some of those messages were shown in court, which allegedly showed Johnson corresponding with other gang members about the people he has killed or recruiting members for specific shootings.
One startling exchange showed the suspect telling a friend that he let a victim get up and run because he had no bullets left.
Johnson's attorney objected to the Instagram messages and videos being shown in court.
At the end of the more than three-hour hearing, the judge raised Johnson's bond to $2.25 million.
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