STAMFORD — Two men were wounded by gunfire in separate incidents after a gunman fired into a city park and a street robbery went wrong, police said Monday.

Gunfire erupted in Hatch Field on Richmond Hill Avenue at 5:15 p.m. Friday, police said. Police received multiple 911 calls reporting shots fired inside the park.

When officers arrived, they found a 38-year-old Stamford man with a gunshot wound to his upper right arm. He was rushed to Stamford Hospital for treatment, police Lt. Tom Scanlon said.

Responding officers had difficulty finding cooperative witnesses, even though they were told that a significant number of people were in the park when the shots rang out, Scanlon said.

Officers determined that an unidentified gunman wearing a ski mask walked into the park and fired multiple shots at a group of people sitting around the pavilion, police said.

Immediately after firing the shots, the gunman fled, police said. Scanlon said they are looking for a surveillance tape of the suspect.

Crime scene investigators combing the scene found multiple shell casings from a single semiautomatic pistol, Scanlon said.

Determining a motive for the shooting has been hampered by a lack of cooperation by witnesses, he said. Police do not know whether the gunman was targeting anyone, Scanlon said. The many people who were with the man when he was shot fled the park before officers arrived, he said.

That shooting was followed by another early Saturday.

Officers were called to Stamford Hospital after a gunshot victim with a wound to his right leg showed up at the emergency room at 4:30 a.m., police said.

The 37-year-old Stamford man told police that he was walking in the area of Ursula Place and Dale Street in the East Side when three men approached and demanded his possessions, Scanlon said. The man refused, and one of the men shot him at close range in the leg, he said.

The three fled after the shooting, and police are working to assemble surveillance tapes of the incident in hopes of determining the identity of the suspects, Scanlon said. He did not release a description of the three men.

Scanlon said it was rare for someone to be shot during a street robbery in Stamford.

The man said that after the shooting, he flagged down a passing motorist, who gave him a ride to Stamford Hospital, police said.

Anyone with information on the shootings is asked to call investigators at 203-977-4414.

jnickerson@stamfordadvocate.com