NEW YORK (REUTERS).- A graffiti artist whose work went on display this month at a prestigious Los Angeles museum was sentenced to 45 days in prison on Wednesday for practicing the same craft in New York.

Angel Ortiz, 44, was arrested three times in March for spray-painting "Laroc" -- his tag -- on walls and buildings in downtown Manhattan.

He was sent to the Rikers Island jail on the third occasion, and so missed his chance to attend to the opening this month of "Art in the Streets," an exhibition of graffiti and street art at the Museum of Contemporary Art in Los Angeles, which includes works by Ortiz.

"I went out to walk my dog, I brought a can with me -- I shouldn't have done it, I knew sooner or later I was going to get grabbed," he told a police officer as he was being arrested the third time, spray-paint can in hand, according to a complaint filed in court by the Manhattan District Attorney's office.

Ortiz pleaded guilty on Wednesday to the top charge against him -- criminal mischief in the fourth degree -- and was sentenced to 45 days in prison, including the month already served.

"He was going on a tear that I haven't seen him do for years," Heidi Follin, who represents Ortiz through her New York gallery, said in a telephone interview after the hearing.

She said he had been affected by the death of his wife in January following an illness.

"There's so much bad graffiti out right now that I think he just went out and showed them who's king," she said.

Ortiz's canvas work, which goes under the name LA II, sells for thousands of dollars, Follin said.

His reputation as a street art pioneer earned him inclusion in the MOCA exhibition, which was described by Jeffrey Deitch, the museum's director, as "the first exhibition to position the work of the most influential artists to emerge from street culture in the context of contemporary art history."

It includes works by some of the best-known proponents of the form, including Jean-Michel Basquiat and Keith Haring, with whom Ortiz collaborated in the 1980s. MOCA did not return calls seeking comment on Monday.

Los Angeles police have said they were concerned that the exhibition might have encouraged an increase in graffiti in the museum's neighborhood. Jason Williams, another graffiti writer in the exhibition, who goes by the name of Revok, was sentenced to 180 days in jail for violating the terms of his probation following a previous vandalism conviction, according to media reports.

(Editing by Jerry Norton)