Lawyers for a journalist who was arrested in Tennessee and then placed in an immigration detention facility said Monday that the government was trying to suppress his reporting and violated his rights of freedom of speech and the press.

Attorneys with the Southern Poverty Law Center have asked a federal court to release Manuel Duran Ortega, a reporter who was arrested earlier this month in Memphis during a demonstration that coincided with days of remembrance of the 50th anniversary of the assassination of Dr. Martin Luther King in that city.

Duran, 42, was working for Spanish-language media outlet Memphis Noticias and has written stories raising questions about local police and their cooperation with federal immigration officials, one of his attorneys at the SPLC said.

“He’s been critical of law enforcement in his reporting and was targeted and retaliated against for that reporting,” said Michelle Lapointe, senior staff attorney with SPLC.

A spokeswoman with the Memphis Police Department and a federal immigration official insisted that Duran’s journalism had nothing to do with his arrest and detention. U.S. immigration officials maintain that Duran’s immigration status was flagged to them only after he was arrested by local police.

Court documents allege that Duran was unlawfully arrested April 3 when he was reporting on a protest of immigration policies. Disorderly conduct and obstruction of a highway charges were dropped but the reporter was picked up by immigration agents after he was released from jail.