David Simon, the creator of The Wire, has again weighed in on unrest in his adopted city of Baltimore, turning his frustration from the protesters to the “army of occupation” of the city’s police.

Simon blamed the “war on drugs” as “the part that seems systemic and connected” to the riots and mass arrests of the past week, telling the Marshall Project – a news site focused on criminal justice – that the drug war had corroded relations between police and black people and hollowed out the police force.

On Monday night a funeral procession for Freddie Gray, a man who died after his spine was nearly severed at the neck in police custody, turned into violent protests and riots that ended with 15 officers injured, some 200 arrests and 144 vehicles burned. On Tuesday, national guard troops moved into the city and imposed a 10pm curfew.

Decades of policy shifts, such as ordinances declaring neighborhoods drug-free, mass arrests on petty charges and skewed crime statistics, turned the police department into a force obsessed with numbers first and police work second, Simon said.

“In these drug-saturated neighborhoods, they weren’t policing their post any more,” he said. “They weren’t nurturing informants, or learning how to properly investigate anything. There’s a real skill set to good police work.

“But no, they were just dragging the sidewalks, hunting stats, and these inner-city neighborhoods – which were indeed drug-saturated because that’s the only industry left – become just hunting grounds. They weren’t protecting anything. They weren’t serving anyone.”

Police, rewarded for high arrest rates and receiving overtime pay for court hours, learned incentives for indiscriminate tactics, Simon continued. In past interviews, Simon has pointed out that many American cities have pursued similar strategies over the years.

“They were collecting bodies, treating corner folk and citizens alike as an Israeli patrol would treat Gaza, or as the Afrikaners would have treated Soweto back in the day. They’re an army of occupation. And once it’s that, then everybody’s the enemy.

“Probable cause was destroyed by the drug war,” Simon said, adding that as long as 30 years ago “there were jokes about: ‘You know what probable cause is on Edmondson Avenue? You roll by in your radio car and the guy looks at you for two seconds too long.’ Probable cause was whatever you thought you could safely lie about when you got into district court.”

Simon framed the problem as one of scale, saying “I know there are still a good many Baltimore cops who know their jobs and do their jobs with some real integrity … [but] it’s clear that there are way too many others for whom no code exists.”

He blamed some of the shifts on the former Maryland governor Martin O’Malley, who as mayor of Baltimore promised to dramatically reduce crime in the city. Baltimore paid out $870,000 in 2006 after the ACLU and NAACP sued the city for civil rights abuses, shortly before O’Malley left office. O’Malley has suggested he may run for the Democratic nomination in the 2016 presidential election.

“Nothing corrects that legacy of a police department in which the entire rank-and-file has been rewarded and affirmed for collecting bodies, for ignoring probable cause, for grabbing anyone they see for whatever reason.”

Gray gave “some Baltimore police the legal equivalent of looking at them a second or two too long”, he said.

“He runs, and so when he’s caught he takes an ass-kicking and then goes into the back of a wagon without so much as a nod to the fourth amendment.”

Although renowned for his pessimistic view of the world – his blog is titled the Audacity of Despair, and The Wire, his most famous show, documents cycles of destructive behavior – Simon described smartphone cameras as “a revolution in civil liberties” that could counteract “the last perfect tyranny” of the American patrolman.

He also repeated his call to “end the drug war” no matter what it took to do it. “Medicalize the problem, decriminalize – I don’t need drugs to be declared legal,” he said. Simon also suggested a solution similar to that of one of his characters: cease enforcing minor drug laws. On The Wire, police major Bunny Colvin’s attempt to end the drug war in one neighborhood ends disastrously. Simon suggests a Baltimore state attorney would have to make the move: “Take away the actual incentive to do bad or useless police work, which is what the drug war has become.”

Simon, whose acclaimed HBO show charted the internecine struggles and failures of Baltimore police, gangs, politics and class, struck a more nuanced tone than in his initial plea for rioters and protesters to “Turn around. Go home. Please.”

That call drew criticism for an implicit trust in city officials to hear protesters’ outrage – contradicting Simon’s own frequent disparagement of those officials – and for the perception of Simon as a would-be cultural translator for the city.

Simon’s work, from The Wire to New Orleans-based Treme and his new project Show Me a Hero, about race relations in Yonkers, New York, often highlights the ways broken institutions fail societies and people. He worked as a police reporter in Baltimore for a decade before becoming a writer for a crime show on NBC.

Simon said some class, race and power issues were intertwined in the problem of police abuses: “The drug war was as much a function of class and social control as it was of racism.”

In the interview Simon conceded his limitations as a commentator: “I guess there’s an awful lot to understand and I’m not sure I understand all of it.”