Born Arizona Clark, in Ash Grove, Missouri, she was known as “Arrie”. In 1892 she married George Barker, in Lawrence Co., MO. The couple had four boys, named Herman (1893-1927), Lloyd (1897-1949), Arthur (1899-1939) and Fred (1901-1935). It appears from the 1910 to 1930 censuses and the Tulsa City Directories from 1916 to 1928 that George was regularly employed in a variety of low-level jobs. From 1916 to 1919, he worked for the Crystal Springs Water Co. In the 1920s, he was variously employed as a farmer, watchman, station engineer, and clerk. An FBI document describes him as “shiftless”, and says that the Barkers paid no attention to the education of their sons, who were all “more or less illiterate”.

George and Arrie’s sons started committing crimes as early as 1910, when Herman Barker was arrested for highway robbery. Over the next few years he and his brothers Lloyd, Fred and Arthur were repeatedly involved in crimes, of increasing seriousness culminating in major robberies and murder. They were inducted into serious crime by the Central Park gang. Herman died on August 29, 1927, in Wichita, Kansas, after a robbery and confrontation with police that left one officer dead. He shot the officer at point blank range in the mouth. Shortly thereafter he killed himself to avoid capture when seriously wounded after crashing his car. In 1928, Lloyd was incarcerated in the federal penitentiary at Leavenworth, Kansas, Arthur “Doc” Barker was in the Oklahoma State Prison, and Fred was in the Kansas State Prison.

George is last listed living with Arrie in the 1928 Tulsa city directory. Whether he was thrown out by Arrie, as some claim, or he left on his own accord when life with a criminal family became intolerable, is not known. According to writer Miriam Allen deFord, it was after Herman’s death and the imprisonment of his other sons, that George “gave up completely and quietly removed himself from the scene.” The FBI claimed that George left Ma for other reasons: because she had become “loose in her moral life” and was “having outside dates with other men”. They noted that though George was not a criminal, he was willing to “profit” from his son’s crimes after their deaths by claiming their assets as next of kin. However, a family friend recalled that George and Arrie argued about their children’s “dissolute life”. While Arrie “countenenced their wrongdoings”, George refused to accept them. The crunch came when George refused to support Lloyd after his arrest, insisting he should be punished for his crime. Arrie did everything she could to get her sons off, no matter what they had done.

From 1928 to 1931 Ma lived in “miserable poverty” in a “dirt-floor shack” with no husband and no job, while all her sons were in jail. This may have been when she became “loose” with local men, as the FBI suggested. By 1930 Arrie was living with a jobless man named Arthur W. Dunlop (sometimes spelled “Dunlap”). She is described as his wife on the 1930 census of Tulsa, Tulsa County, Oklahoma. Things improved for her in 1931 after her son Fred was released from jail. He joined former prison-mate Alvin Karpis to form the Barker-Karpis gang. After a series of robberies, Fred and Karpis killed sheriff C. Roy Kelly in December 1931, an act that forced them to flee the territory. Ma and her lover Dunlop traveled with them, using various false names during their itinerant crime career. A wanted poster issued at this time offers $100 reward for the capture of “Old Lady Arrie Barker” as an accomplice. After this, she was usually known to gang members as “Kate”.

When Arthur was released in 1932, he joined Fred and Karpis. The core gang was also supplemented by other criminal associates. The gang moved first to Chicago, but decided to leave because Karpis did not want to work for Al Capone. Racketeer Jack Peifer suggested that they should come to St. Paul, Minnesota, a town which had a reputation at the time as a haven for wanted criminals. The Barker-Karpis gang’s most infamous crimes were committed after the move to St. Paul, during their residency in a string of rented houses in and around the town. In St. Paul, the gang operated under the protection of the city’s corrupt police chief, Thomas “Big Tom” Brown, and under his guidance, graduated from bank robbers to kidnappers.

Ma’s common-law husband Arthur Dunlop was said to be loose-lipped when drunk, and was not trusted by members of the gang. He was described as a “pain in the ass” by Karpis. While at one hideout, a local resident identified the gang from photographs in True Detective magazine, and told the police. Brown tipped off the gang, and they escaped. Wrongly believing that Dunlop’s loose lips had given them away, they apparently murdered him while traveling. His naked body, with a single bullet wound to the head, was found near Webster, Wisconsin. Though Tom Brown’s involvement in the gang’s escape could not be proved, he was demoted to the rank of detective and was later dismissed from the police force. For a time the gang relocated to Menomonie, Wisconsin.

During this time, Fred Barker stashed Ma Barker in a variety of hotels and hideouts. The purpose was to keep her from learning much about the gang’s crimes, as well as to separate her from the gang’s girlfriends, with whom she did not get along. Indeed the FBI later claimed that Ma would try to break up any relationships, so that “other women in the gang” did their best to avoid Ma. By 1933 most of the gang were back in St. Paul, where they planned and carried out two kidnappings of wealthy local businessmen. After successfully obtaining $100,000 ransom after abducting William Hamm, they then arranged the kidnapping of Edward Bremer, from which they netted a $200,000 ransom. This brought the gang to the FBI’s attention, so they left St. Paul, renting a series of Chicago apartments for Ma Barker while they tried to launder the ransom.

FBI agents discovered the hideout of Barker and her son, Fred, after Arthur “Doc” Barker was arrested in Chicago on January 8, 1935. A map found in his possession indicated that other gang members were in Ocklawaha, Florida. The FBI soon located the house where the gang was staying after identifying references to a local alligator named “Gator Joe”, mentioned in a letter sent to Doc. They had rented the property under the pseudonym “Blackburn”, claiming to be a mother and sons wanting to vacation in a country retreat.

Agents surrounded the house at 13250 East Highway C-25 on the morning of January 16, 1935. Unknown to the FBI, Karpis and other gang members had left three days before, leaving only Fred and Ma in the house. Ordered to surrender, Fred opened fire; both he and his mother were killed by federal agents after an intense, hours-long shootout. Allegedly, many local people came to watch the events unfolding, even holding picnics during the gunfire. After gunfire ceased coming from the house, the FBI ordered local estate handyman Willie Woodbury to enter the house wearing a bulletproof vest. Woodbury reported that there was no one inside alive.

Both bodies were found in the same front bedroom. Fred’s body was riddled with bullets, but Ma appeared to have died from a single bullet wound. According to the FBI’s account, a Tommy gun was found lying in her hands. Other sources say it was lying between the bodies of Ma and Fred. Their bodies were put on public display, and then stored unclaimed, until October 1, 1935, when relatives had them buried at Williams Timberhill Cemetery in Welch, Oklahoma, next to the body of Herman Barker.