4-year-old Richard Jones has been charged as an adult with third-degree murder and criminal conspiracy after turning himself in for beating 73-year-old James Lambert Jr. to death in Philadelphia last month.

The teenager had allegedly confessed to the crime alongside his 10-year-old brother, Fox 29 reported. However, the younger sibling was reportedly released after not being charged, added the outlet.

Under Pennsylvania law, juveniles must be charged as adults for murder, The Philadelphia Inquirer reported.

The two boys were among seven juveniles captured on video who allegedly assaulted Lambert with a traffic cone on June 24 in the northern area of the city, ABC News and NBC Philadelphia reported. Police said that Jones was the first to hit the man with a cone, Fox 29 added.

Police have also identified a third female suspect who is seen striking the victim at least three times in the surveillance video, Fox 29 reported.

“The teens struck the victim several times with objects, knocking the victim to the ground causing injuries to his head,” the Philadelphia Police Department said in a statement. Lambert was hospitalized and died of his injuries the following day, they added.

The Philadelphia Police Department did not immediately return PEOPLE’s request for comment.

According to Danny Freeman from NBC Philadelphia, Lambert’s relatives are in shock. “His family tells me they’re heart broken and they saw him just hours before he was attacked. They’re in disbelief a group of kids did this,” Freeman tweeted.

Last week, police released a surveillance video of the assault, which happened around 2:30 a.m. The suspects are described as four Black males and three Black females “who appear to be in their early to mid-teens,” authorities added in their blotter statement.

In the video, the suspects chased Lambert and repeatedly hit him in the head with the traffic cone. One suspect filmed the assault on a cellphone. Philadelphia Police Department Homicide Capt. Jason Smith told the outlet that at least two of the group members participated in the beating.

Authorities are asking the parents of the others involved to reach out.

“The message I would like to put out there is to the parents of these juveniles, if they are aware that their son or daughter is involved in this incident, I think that the best course of action would be for them to contact an attorney and then contact the homicide unit,” Smith said, per WPVI.

A summer curfew of 10 p.m. for teens between the ages of 14 and 17 recently went into effect through Sept. 29, according to NBC. Previously, the curfew was midnight. Those under 13 are required to be home by 9:30 p.m.

Last Friday, the Philadelphia Police Department announced a $20,000 reward for information leading to an arrest and conviction in Lambert’s beating death.

Anyone with information is asked to contact the Philadelphia Police Department Homicide Unit at 215-686-3334/3335.