SAN DIEGO -- The discovery of a pipe bomb alongside Interstate 5 in the La Jolla Village area forced a full shutdown of a stretch of the regional route for more than an hour Friday and a lengthier partial shutdown.

Late Friday morning, the person suspected of assembling the homemade explosive device led authorities to where he had tossed it, inside a backpack, when his car broke down on the freeway yesterday, according to police.

The California Highway Patrol initially shut down one lane near Genesee Avenue and several connector ramps as a sheriff's bomb squad investigated, the CHP reported.

In the early afternoon, authorities shut down the entire interstate between State Route 52 and I-805. The explosives experts then used remote-controlled detonations to blow open the backpack and destroy the object.

The closure led to stop-and-go traffic along the freeway for miles in both directions.

About 3 p.m., the northbound side of I-5 was reopened, CHP public affairs Officer Larry Landeros said. The southbound lanes remained closed for almost another hour pending completion of police operations in the area.

Even after the freeway was fully reopened, traffic remained extra heavy along the I-5 corridor as the evening commute got under way, the Highway Patrol reported.

The whole mess stemmed from a citizen's report received by the Oceanside Police Department Thursday, OPD Sgt. Leonard Mata said.

The tipster provided information about an alleged plan by a 46-year-old Oceanside resident to detonate an explosive device at the Vista Courthouse.

Detectives determined the suspect's identity and contacted him. During a subsequent interview, the man admitted to making a pipe bomb and then tossing it alongside the San Diego-area freeway, Mata said.

As of Friday afternoon, the alleged courthouse threat remained under investigation, and the suspect, identified as Michael Buffalo, had not been arrested, the sergeant said.