A teenaged Moroccan rapper is in juvenile detention on a variety of charges that include distorting the words of the national anthem, immorality and encouraging drug use, colleagues said Saturday.

Othman A, known as Mr Crazy, was arrested August 9 and is being held in a juvenile facility in Casablanca, a city of five million people from whose poor neighbourhoods he draws his inspiration.

Less than a month ago, rapper Mouad Belghawat, a voice of Morocco's February 20 protest movement, was released from jail after serving a four-month sentence for assaulting police.

The authorities, who could not be reached for comment, have acted in response to the distribution of three videos in which the 16-year-old singer acts out scenes of violence and raps about daily life in Casablanca.

One of the clips has had nearly 950,000 hits.

Othman A appeared before a juvenile judge on Friday, and a new hearing in his case was scheduled for October 18, a friend said.

Two colleagues, a videographer and someone who appeared in one of the videos, were arrested at the same time as Othman A but released several days later, according to Belghawat.

Known as Lhaqed, Belghawat was freed from prison in Casablanca on September 18.

According to him, Othman is simply "a youth who recounts his reality. You can't judge him for his creativity, as if he were a thief."

And Othman's mother says he "does not know why he has been arrested. When I go to visit him, he does nothing but weep."

Belghawat was arrested at a football match in May and accused of drunkenness in public, assaulting security agents and touting tickets on the black market.

Human Rights Watch warned of political motives behind his jailing and demanded any appeals trial admit key evidence the judge rejected in convicting him on July 1.

The Casablanca court also ordered him to pay 15,000 dirhams ($1,720) to the two policemen he allegedly assaulted, as well as a 500-dirham fine.

Lhaqed -- The Rancorous One in Arabic -- was convicted in 2012 for the YouTube video of a song he wrote called "Dogs of the State," which denounced police corruption and was deemed an affront to Morocco's entire police force.

The video showed a policeman with the head of a donkey.

The musician was a public face of the February 20 movement in 2011 born out of the Arab Spring protests sweeping the region that year and demanding extensive reforms in Morocco.

He was awarded an "integrity" prize by Transparency Morocco while serving his earlier sentence, and released in March last year.