Which US president was arrested and accused of running someone over with a horse, but not convicted?

Franklin Pierce was the 14th president of the United States, and he was arrested while serving as president for running down an old woman while on horseback. Pierce was never convicted of a crime connected to the incident, due to what the courts described as insufficient evidence. A newspaper story from 1927 that reports on the incident in which Pierce ran over a woman with his horse notes that the President was likely drunk at the time of the accident. President Pierce was known to have a drinking problem throughout his adult life, and in fact his struggles with alcohol brought about the cirrhosis of the liver that ended up killing him.