Haunting sonar images show Baltimore bridge wreckage at bottom of channel

Three sonar images provided by the U.S. Navy's Naval Sea Systems Command (NAVSEA) and the Supervisor of Salvage and Diving (SUPSALV) show the wrangled remnants of the Francis Scott Key Bridge following its early morning collapse on March 26. The images were posted on X, formerly known as Twitter, by the U.S. Army Corps of Engineers.

"These 3D images show the sheer magnitude of the very difficult and challenging salvage operation ahead," a Facebook post by the USACE read. "The underwater sonar imaging tool, known as CODA Octopus, is the primary survey tool used by divers."

NAVSEA officials used an Echoscope, which according to its manufacturers at CODA Octopus Group, is "the world's highest resolution real-time 3D/4D sonar technology."

Sonar technology uses sound to send out acoustic signals, which then bounce off of solid objects. Based on signal strength and how long it takes to return, the technology then proceeds to generate detailed maps and images -- which prove crucial in recovery efforts.

Six construction workers were killed in the collapse. Last week the body of 38-year-old Maynor Yasir Suazo-Sandoval was recovered by dive teams. The bodies of three victims remain unrecovered.

This article was originally published on NBCNews.com