Authorities in the United States say they cannot identify one person or company responsible for a deadly Berkeley balcony collapse last year.

Five Irish students and an Irish-American lost their lives, while seven others were injured.

In statements released through their lawyers, all 13 families thanked the district attorney's office for their investigation.

While the family of Ashley Donohoe also say the companies have been allowed to hide behind prior wrong-doings, and that other structures may be constructed in a similarly poor fashion.

Following a nine-month investigation, the Alameda County district attorney Nancy E O'Malley said there was insufficient evidence to pursue criminal manslaughter charges.

The investigation encompassed witness interviews, reviews of building plans, logs, inspection records and maintenance records.

It also involved investigators from multiple state agencies and industry experts.

Alameda Chief Assistant District Attorney Kevin Dunleavy told Newstalk Breakfast their extensive investigations found several individuals are at fault.