A woman on a motorcycle was killed and 10 people were injured in a pair of multiple-vehicle collisions Thursday in an expressway tunnel in Shimada, Shizuoka Prefecture, police said.

Five vehicles and a motorcycle collided in the 2.6-km-long tunnel on the Shin-Tomei Expressway around 10:10 a.m., injuring seven people. Another crash, which involved three vehicles, occurred around 100 meters from the site of the first accident, leaving three injured. Sumiko Tominaga, 51, was later pronounced dead, they said.

Police arrested Yu Daibo, a 52-year-old truck driver from Hiroshima Prefecture, at the site of the first pileup on suspicion of professional negligence resulting in death and injury.

Daibo told investigators that he caused the accident as he was checking email on a smartphone while driving.

The first accident occurred as the truck hit the motorcycle, causing the four other vehicles to collide. The second accident was apparently caused due to a traffic jam stemming from the first incident.

At the time of the accidents, the inbound two-lane road was restricted to one lane for tunnel checks, according to Central Nippon Expressway Co., the highway operator.