A man accused of opening fire at a July 4th parade near Chicago has now been charged with seven counts of murder, officials say.

According to foreign media, the Telegraph reports, Robert Crimo, 21, would be sentenced "for the spree of murders he has committed against our community," said Lake County state prosecutor Eric Rinehart.

The attack in Highland Park left seven dead and more than 30 others injured.

Rinehart added that several more charges would be filed before the investigation was completed.

"These are just the first of many charges that will be brought against Crimo," he said.

"I want to emphasize this.

There will be more charges."

The suspect is reportedly accused of firing 70 rounds from a high-powered rifle into the crowd and disguised himself as a woman so he could escape with the fleeing victims.

After an eight-hour manhunt on Monday, police arrested Crimo and he was found with a second rifle similar to the one used in the attack.