Over 100 rounds fired in DC shooting that injured 4: Police

A man opened fire from his apartment window in a "sniper-style" shooting in Washington, D.C., on Friday, injuring four people, before the suspect took his own life.

D.C. police responded to the Cleveland Park and Van Ness areas around 3:20 p.m. and found three shooting victims -- two men and a 12-year-old girl, authorities said.

The two men are in critical but stable condition, while the child was hospitalized in stable condition with a minor gunshot wound, police said at a Friday evening press briefing. One of the men was a retired Metropolitan police officer, authorities said.

A fourth victim who sustained a gunshot wound later came forward to police. The victim -- a woman in her mid-60s -- had a graze wound to her upper back and received medical treatment on site, police said.

The suspect died by suicide in his apartment when police closed in, according to Metropolitan Police Department Police Chief Robert Contee.

Contee said a tripod was set up in the fifth-floor apartment and the man appeared to be targeting people at random on the street below.

Six guns were found in the suspect's apartment, including both long guns and handguns, as well as "multiple, multiple rounds" of ammunition.

Contee said "over 100 rounds" were fired from a long gun in the incident.

"There are probably going to be a lot of bullet holes we're going to find," he said.

Police identified 23-year-old Raymond Spencer, of Fairfax, Virginia, as a person of interest "based upon the things we have seen on social media," Metropolitan Police Department Assistant Chief Stuart Emerman told reporters during an update Friday night.

While Contee would not officially confirm that Spencer was the person found dead in the apartment, he said they were no longer looking for anyone in connection to the shooting.

Contee confirmed that a social media video of the shooting appeared to be credible, but was unsure if it was streamed live or recorded and later posted.

"Today, evil reared its ugly head in our community," Contee said.

"It speaks to the depravity of some of the individuals we have to face in our community. ... There could've been more damage done, more lives lost," Contee later added.

Earlier in the evening, while still searching for Spencer, Emerman said, "We'd like to speak to Mr. Spencer, figure out if he has any role in this or any connection to this. Hopefully that'll lead us in a direction to identify what happened here and why."

Contee said they still do not have a motive in the shooting. The suspect was not previously arrested, Contee added.

Students from the Edmund Burke School who were on lockdown during the incident are now being reunified with families, officials said Friday night.

"We have experienced this too much in our country. The epidemic of the gun violence, the easy access to weapons has got to stop," D.C. Mayor Muriel Bowser said. "People should not be scared taking their children to school."

The FBI Washington Field Office confirmed in a statement to ABC News that it is assisting police in the response.

"The situation is ongoing and the FBI will provide appropriate personnel and resources, as requested and needed," the office said.

Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives' Washington Field Division are also helping with the shooting investigation.

ABC News' Luke Barr and Jack Date contributed to this report.