No one can say exactly why Henry Chavez killed Luis Ravanales Hamington Orozco.

His attorney gave it a try Monday, suggesting paranoia fueled by two things: use of PCP and the anxieties of being 3-foot-11. The judge didn’t buy it, sentencing Chavez to 30 years, the maximum possible under a plea agreement.

“What you did is you executed that man,” Montgomery County Circuit Court Judge Eric Johnson told Chavez.

The invoking of PCP as a mitigating factor echoes two recent high-profile cases in Montgomery and underscores increased use of the drug, which can cause hallucinations. “That’s the main drug that I wish would disappear,” said Lt. Marcus Jones, head of the county police’s drug enforcement section.

Jones said PCP use had started falling in the late 1990s but returned in 2007 and 2008. A new breed of users is demanding the drug just as some of the old PCP dealers are getting out of jail. “Some of those individuals are getting out, and they’re back to their old ways,” he said. “And they’re finding new customers.”

Chavez’s case dates to the night of May 27, 2010, when he walked up to four men gathered outside an apartment building along Georgia Avenue in Silver Spring, about 10 blocks north of the Capital Beltway. Words were exchanged, and Chavez shot Orozco three times in the head.

Chavez spoke in court Monday, turning to the victim’s family members. “I am truly, truly, truly sorry,” he said.

Police learned that Chavez had associates in the MS-13, or Mara Salvatrucha, gang, and suspected he was a member, according to law enforcement sources. Also, even though Chavez was born in and grew up in the District, he fled after the killing to El Salvador, which has strong ties to the gang.

Louis Martucci, Chavez’s attorney, has said in interviews that the crime had nothing to do with gangs. In court Monday, he told Johnson that Chavez’s PCP use and height could have played a role.

“None of this is by way of justification,” Martucci said. He added: “What I am suggesting is that his use of PCP, which he claims he used as recently as a half-hour to an hour prior to this incident, could have resulted in an exacerbation of his paranoia of feelings of being threatened, particularly in light of his size.”

Under the terms of Chavez’s sentence, he can be released on parole only with the governor’s approval.

In court was Jenny Ochoa, 24, Orozco’s girlfriend at the time of the murder. “I think that’s no justification, not your size,” she said after the hearing.

Henry Chavez appeared in court on drug charges in 2008.