"We're still continuing to look at a lot of different areas," Laurel Mayor Craig Moe said. "We encourage people to say something if they see something."
Laurel resident Sharon Wentland said she was shocked when she first heard about the playground fires in March.
"It's amazing how much they damaged them," Wentland said. "What is wrong with people?"
"I really want to know who did it," said Jocelyn Fogle, 10, who lives within walking distance of Discovery Community Park.
"(Discovery) was a very fantastic park," she said. "I just wasn't happy" when it burned.
Jenny Ripley, a Laurel resident since 1967, said she had never seen "such mindless destruction."
"Laurel shouldn't be in the news for that," Ripley said.
Following the March playground fires, city officials organized a Community Fun Day at Discovery Community Park in an effort to reach out to residents and keep them updated on the repair process. A second Community Fun Day was held in April at Emancipation Community Park.
"It's positive that the (city) council understands and appreciates the fact that kids need to go and play and be themselves," Ripley said.
Karon Gatling, 11, said she was glad to see the Discovery Community Park playground fully repaired.
"I'm happy because kids can play on it again," she said. "It was hard to find other parks."
Moe said that the city has not had any major issues with its parks since the fires in March.
"We're not going to tolerate it," Moe said. "People are going to come together in the parks and have good times and be safe."
Brady said he remains optimistic as the investigation continues.
"We do believe someone out there knows who has committed these crimes, he said. "We continue to seek help from the community for providing any information."
To anonymously leave a tip about the arson incidents, contact the Laurel Police Department's tip line at 301-498-7465 or the Prince George's County fire tip line at 301-77-ARSON.
This story has been updated.