They rushed to Ukraine by the thousands, many of them Americans who promised to bring military experience, money or supplies to the battleground of a righteous war. Hometown newspapers hailed their commitment, and donors backed them with millions of dollars.

Now, after a year of combat, many of these homespun groups of volunteers are fighting with themselves and undermining the war effort. Some have wasted money or stolen valor. Others have cloaked themselves in charity while also trying to profit off the war, records show.

One retired Marine lieutenant colonel from Virginia is the focus of a U.S. federal investigation into the potentially illegal export of military technology. A former Army soldier arrived in Ukraine only to turn traitor and defect to Russia. A Connecticut man who lied about his military service has posted live updates from the battlefield — including his exact location — and boasted about his easy access to American weaponry. A former construction worker is hatching a plan to use fake passports to smuggle in fighters from Pakistan and Iran.