In BRANDED AS REBELS, page 82, by Joanne Eakin & Donald Hale, this is what they have on Alvin Cobb: "A Colonel who assembled a small band of guerrillas in Missouri in July of 1861. On July 18, 1861 he and his band murdered Major Benjamin Sharp, a prominent resident of Danville, MO and Lt. A Yager [Jager] a Federal officer near Martinsburg, MO. Cobb's relatives were all old settlers in the western part of Montgomery County where he lived. He was about middle age when the war started. He had only one arm, the other had been accidently shot off. At the start of the war he began guerrilla warfare. It was believed by some that he did not have a commission. He was in many small fights such as at Mr.Zion, Fulton, Moore's Mill and one or two others and in 1862 was with Porter. He was listed as being in Callaway County in June 1862. Cobb later went to the Indian Territory and by 1885 was living in California. Ref: O.R.; Montgomery, 1885; Shelby, 1884; Block [said he was with Porter, he commanded groups and was killed at Portland, MO in 1862]."
Same book, same page by Eakin & Hale on Ike Cobb: "Guerrilla. In the fall of 1861 with a band of 15 men, made a raid on and robbed the store of Hugo Monnig, a German Unionist who lived on the road from Danville to Rhineland, 1/2 mile from the bottoms. Ref: Montgomery, 1885."
The Montgomery and Shelby listed as references are "The History of Montgomery County, Missouri. St. Louis, 1885" and "History of Shelby County, Missouri. St. Louis, 1884". I hope this helps.
Rose Mary Lankford