a couple of websites detailing Utah Beach landing:
extracted from The Corps of Engineers: The War Against Germany
http://www.army.mil/cmh-pg/BOOKS/WWII/utah/utah3.htm
The first wave consisted of 20 LCVP's, each carrying a 30-man assault team from the 2d Battalion, 8th Infantry. [The second wave comprised another 32 LCVP's with additional troops of the 2 assault battalions, some combat engineers, and also 8 naval demolition teams which were to clear the beach of underwater obstacles. The third wave, timed for H plus 15 minutes, contained 8 more LCT's with dozer tanks. It was followed within 2 minutes by the fourth wave, mainly detachments of the 237th and 299th Engineer Combat Battalions, to clear the beaches between high and low water marks.
Note: 50% of the Naval demolition teams were comprised of Army engineers, unknown units.
Clearing the Beaches
Such clearing of beach obstacles as was necessary was the mission of a special engineer force which was scheduled to land directly after the 8th Infantry. The engineer elements were organized as a Beach Obstacle Task Force, commanded by Maj. Herschel E. Linn of the 1106th Engineer Combat Group. They were to clear four 50-yard gaps in the obstacles on each beach from the high water mark seaward by hand-placed charges and tank dozers. Naval demolition teams were to destroy all obstacles under water and Army engineer teams were responsible for those above water. Army combat engineers were from the 237th Engineer Combat Battalion.
Companies A and C of the 237th Engineer Combat Battalion, landed with the 8th Infantry at H-hour.
Other units wereThe arrival at UTAH on 10 June of the 38th Engineer General Service Regiment, an Advance Section (ADSEC) unit attached to the 1st Engineer Special Brigade./size]
An account of the Malmedy massacre:
http://www.historynet.com/magazines/world_war_2/3030591.html
"While the survivors of Battery B of the 285th Field Artillery Observation Battalion were being assembled in a field immediately adjacent to, and south of, the Café Bodarwé, three trucks from Company B of the 86th Engineer Battalion came up the hill from Malmédy and, after halting behind the ambulances at the rear of Battery B, were fired on by the Germans. Five of the men in these trucks managed to get away, although one of them was wounded and a sixth was captured.:
Note: There were many other Infantry, armored & engineer units in the imediate vincity of Malmedy St Vith and the germans had taken more prisoners of various units prior to the capturing convoy.
Hopefully this will narrow the search down a little & give you a place to start researching.
Larry