NEW ORLEANS (Reuters) - New Orleans police on Monday released photos that they said show a suspect in the shooting at a Mother’s Day parade in which 19 people, including two children, were wounded.

New Orleans Police Superintendent Ronal Serpas told reporters on Monday that investigators are making significant progress on the investigation, although no one has yet been arrested.

“I can assure whoever did this, we know a lot more about you than you think we do,” Serpas said at a press conference. “And my recommendation to you is to collect yourself and turn yourself in.”

The image singling out the suspect does not clearly show the face, and police, who released the photographs on YouTube (here&v=BYwDHfAJhic), asked for the public's help in identifying and finding the person. A reward for information that might help find the shooter was increased from $5,000 to $10,000.

Ten men, seven women and a girl and a boy, both 10 years old, were hit when one or more people opened fire at the parade on Sunday.

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Serpas said he has not ruled out that the shooting was gang related.

Investigators on Monday were still trying to figure out if there was more than one shooter and more than one weapon, Serpas said.

The photographs, taken from a surveillance video, first show crowds of people in a street, and then the crowd is seen scattering and ducking. The final image focuses on what appears to be a man in a white shirt leaving the scene on foot as other people are lying on the pavement. The image does not clearly show his face.

Two victims underwent surgery and the children were grazed but in good condition, police said. It was unclear if the victims were marching or watching the parade.

Violent crime in New Orleans ranks above the national average in FBI surveys. A poll of residents in 2010 found crime to be their greatest concern.