Anger mounted in the Syrian city of Latakia, a stronghold of President Bashar al-Assad, following the killing of an officer in the Syrian army allegedly by a relative of the president.

In a video published online on Sunday, the brother of slain officer Hassan al-Sheikh called on residents to hold daily sit-ins over the death of his brother, believed to have been killed by Suleiman al-Assad, the son of Bashar’s first cousin.

The brother accused the Assad regime of providing impunity to the assailant.

It is rare for citizens from to the Alawite sect - which Assad belongs to - to speak out against the ruling regime publicly. Alawites have largely sided with Assad as he battled the opposition ranks, which are largely from the Sunni sect.

Reports suggest that the killing happened on Friday following a traffic feud in Latakia near Assad's village.

The governor of Latakia, in an interview with state-sponsored Radio Sham FM, said that investigation into the crime was under way, adding that "no one is above the law".

Sham FM spoke with the brother of al-Sheikh who said he saw Suleiman al-Assad killing his brother in front of his eyes.

The radio's correspondent said that, a day after the death, many people gathered at al-Zarraa square in the city, lit candles and called for the punishment of the killer.

Dignity of the Syrian officer

Residents in the city told Al Jazeera that Suleiman, who was driving a black Hummer without car plates, was angered when he was overtaken by the al-Sheikh’s car at a crossroads.

He reportedly got out of his car holding an AK-47 and pumped seven bullets into the chest of the officer.

In the video circulated online, residents are heard saying: "We demand the execution of Suleiman." One woman in the crowd screams: "we will come [for the sit-ins] everyday."

A man in the video is heard saying: "When it comes to men driving without car plates and committing thuggery and killing any of us, we are worth nothing. Hassan is our martyr. We want to defend the dignity of the Syrian officer."

Suleiman’s father, Hilal al-Assad, a first cousin of the president, headed the defence forces in Latakia before his death last year in battles with rebels in the Kasab suburb of the city.

Louay Hussain, a prominent Alawite opposition activist, wrote on his Facebook: