Before Denver City Council’s decision Monday to ask voters to approve a 5 percent sales tax for marijuana, Denver District Attorney Mitch Morrissey held the floor and presented a startling statistic about the pot industry.

“We have had 12 homicides related directly to medical marijuana,” Morrissey said. “We have had over 100 aggravated robberies and home invasions. Many of you probably didn’t read about the double-execution-style homicide that we had here in Denver, where people were laid down on the floor and executed because they were running a medical marijuana outlet.”

But on Tuesday, Morrissey said the numbers he presented the day before to the council were “loose figures” and none of the homicides was in an established medical marijuana facility.

Medical marijuana industry officials at Monday’s meeting had been taken aback by Morrissey’s statements.

Michael Elliott, executive director of the Medical Marijuana Industry Group, argued after the meeting that the district attorney was unfairly casting a bad light on the legally regulated storefronts when the city is preparing its regulatory framework for a new industry to sell marijuana to adults in retail facilities.

“All of this violence associated with marijuana is being blamed on the good players,” he said. “The implication is that it is our fault. There needs to be a distinction (of those incidents) between those who are doing it legally and those who are doing it illegally.”

Morrissey’s office Tuesday sent an e-mail containing news accounts of nine homicides since 2007 that it said were marijuana-related. The Denver Post interviewed homicide detectives in Denver and Aurora to review his claims.

The Post found that many of the cases were home invasions — not robberies of brick-and-mortar businesses — and it was unclear whether victims in the homes were legally growing and selling marijuana.

At Monday’s meeting, Morrissey stressed that the council needs to know about the violence exploding in the cash-driven medical marijuana industry and that council members should expect the same thing when Colorado begins selling retail marijuana.

“You don’t read about the impacts of medical marijuana, and one of the impacts is 12 murders,” he told the council. “That is what you are seeing unreported by all of the media outlets. That is what I find most disturbing about this. Twelve people have lost their lives, laid down on the floor and were killed. … And nobody is talking about it.”

Morrissey said his office will need extra money to prosecute the crimes that will come with the expanding marijuana industry.

The council later agreed to ask Denver voters in November to approve a 5 percent sales tax to help pay for expenses predicted for all city departments.

The most dramatic incident that Morrissey recounted to the council was the double homicide that occurred March 24, 2011, at the Windsor Court Apartments.

Amara Kamoh Sayon, 22, and Cherise Houston, 25, were shot to death. Morrissey said they were killed execution-style. The case remains unsolved. A Denver homicide investigator on Tuesday would not say whether there was a marijuana connection.

He did say one suspect in that crime was killed a week later in an Aurora home invasion. In that March 31, 2011, slaying, Athina Munoz used an assault-style rifle to kill Jovan Rivers and Harrell King at the Sable Landing Condos. Morrissey said Munoz was a medical marijuana caregiver protecting her home.

Aurora police said Rivers and King came to the condo because they believed medical marijuana was being sold out of the home. Charges were not filed against Munoz because the shooting fell under the state’s Make My Day Law, which allows homeowners to lethally defend themselves. The woman, who was not a caregiver, was illegally growing marijuana, Aurora police said.

Morrissey also pointed to other incidents involving caregivers growing and selling marijuana out of their home.

Caregiver Richard Nack was killed in May 2012 at his home, and medical marijuana activist Ken Gorman was killed in his west Denver home in 2007. Peter Bellar was sentenced to life in prison without parole for the January 2010 killing of medical marijuana provider Douglass Singleton.

Morrissey also cited another 2010 incident in which people living in a home near the University of Denver were growing and selling medical marijuana. Would-be robbers burst in the home and tied up the residents. But one resident got free, wrested the gun from the robber and shot him dead. The dead man was Daniel Deleon, and the shooter, who was never named by police, was cleared under the Make My Day Law.

“My point is people are targeting and turning these folks into victims because there is large qualities of cash there,” Morrissey said. “They are all part of the medical marijuana business, in my mind. When you are setting the reasonable tax on this, you should consider these impacts as well as the other impacts.”

Councilwoman Susan Shepherd said she wondered whether Morrissey’s statements were an indictment on the industry or the black market.

“It was certainly dramatic, for sure,” she said. “It’s hard not to listen to that and not be influenced by it.”

Jeremy P. Meyer: 303-954-1367, jpmeyer@denverpost.com or twitter.com/jpmeyerdpost