CAIRO, (AP) – Egyptian security forces beat and arrested dozens of protesters on Sunday when they attempted to march through downtown Cairo in the latest demonstration against police brutality following the death of young man, witnesses and police said.

For the past 10 days, protesters have taken to the streets in demonstrations over the death of Khaled Said, a 28-year old Alexandria businessman who was found dead after an encounter with plainclothes security men. According to witnesses, at its peak Sunday’s protest involved a couple of hundred people.

A security official confirmed at least 40 people were detained during the march in downtown Cairo. He spoke on condition of anonymity as he was not authorized to speak to the media.

Activists say Said’s death is an example of routine police torture in Egypt. The government denies torture is systemic and says the incident is under investigation.

“We came to protest police torture and we will not leave until those who were detained today are freed; this is exactly why we are here in the first place,” human rights activist Aida Saif al-Dawla said at the protest.

After police stopped activists from gathering in the main city square, they marched through downtown Cairo, prompting a violent response from security, said those involved.

“Police cars stopped in the middle of the street as security officers came out and started to beat people … girls and guys, it didn’t matter to them,” said Philip Rizk, an activist and documentary filmmaker who was at the protest.

“As I was shooting video on my phone, a police officer hit me across the face and tried to take it away from me,” he added.

Other journalists present confirmed that police interfered with their efforts to cover the protest.

“Despite the ongoing violence demonstrators face, activists will continue to voice their concerns in the upcoming weeks,” said Ahmed Maher, one of the protest’s organizers.

Said’s death has become a rallying point for government critics who say it is an example of rampant police abuses made possible by a three-decade-old emergency law they describe as a central tool of repression by President Hosni Mubarak’s regime.

Said died on June 6 after being approached by plainclothes policemen at an Internet Cafe in the port city of Alexandria. His family and human rights groups cite witnesses that he was beaten to death in the street. A picture circulated after his death showed his jaw split, teeth broken and blood pouring from his head.

Police officials denied Said died of torture, saying the young man was wanted for various crimes, and died after attempting to swallow a packet of drugs and choking to death.