A Newport Coast man is being interviewed by Laguna Beach police in an ongoing case of dirty diapers being dumped on public streets.

The 67-year-old suspect's identity is being withheld, Capt. Jason Kravetz said in a press release.

The reports of diaper dumpings in Laguna go back to May. Corona del Mar had similar incidents during the past year.

Detectives have been working on the case for the past few months, but got a break Monday night, according to the release.

While setting up surveillance on North Coast Highway, police discovered bags of diapers that had not yet been hit by cars. They appeared to have been recently dumped.

While looking through the bag, an officer came upon an envelope attached to the diaper that was addressed to a medical office in Fullerton.

An employee of the office lives in the Newport Coast area, the release said.

On Tuesday night, officers watched the employee's home in a gated community and paid attention to any movement of two vehicles in the garage: a Bentley and a Lexus.

At 10:45 p.m. the suspect drove off in the Lexus. Police followed him to Laguna Beach. He made a quick U-turn near Irvine Cove and headed north.

This caused detectives to initiate a traffic stop near Reef Point and Coast Highway. Once police got close to the vehicle, they spotted a large bag of diapers in the passenger seat, the release said.

The suspect was not arrested at the scene. Laguna Beach detectives will collaborate with Newport Beach investigators to merge the cases and present them to the Orange County district attorney's office for prosecution of illegal dumping.

Previously, the dirty diapers had been reported on the southbound lanes of North Coast Highway between Irvine Cove and Emerald Bay during the spring and summer.

"Not only is it a biohazard to throw human waste onto a city street, but there were occasions when vehicles would drive over the diapers causing them to stick to undercarriages and tires. This caused the waste material to spread even greater distances," the release said.

joanna.clay@latimes.com

Twitter: @joannaclay