A private group called History Flight has used ground-penetrating radar to find the remains.
“520 of the Marines and Corpsmen who died on Tarawa are still listed as MIA. A private group called History Flight, which is based out of Marathon, Florida, has used ground-penetrating radar to find the remains of some 139 Marines. On July 26, 2015, History Flight brought 36 of them on the first leg of their return home to Joint Base Pearl Harbor-Hickam in Honolulu, Hawaii.
The identification process is now underway under the auspices of the Defense POW/MIA Accounting Agency. When the identifications are completed, the Marine Corps will return the remains to their families. A military ceremony was held there to mark their return on Sunday, July 28th, 2015.”
— Read on blog.theveteranssite.greatergood.com/marines-tarawa-island/