runs in threes ???

ummm I don't know what to think:

On July 26,2008 my sister-in-law Kim, died in her sleep. She was only 44 and no known reason explained her death. There were 6 pallbearers at her casket during the funeral.
6 pallbearer were: 1. her husband, Steve (my husband's brother) 2. my husband (who flew in from Phoenix) 3. Steve's long-time best friend (drove in from Mississippi) 4. Steve's long-time best friend (lives in the same town in Arkansas) 5. Son-in-law (lives with Steve&Kim) 6. Another Son-in-law (lives with Steve&Kim)

Steve's long-time friend's wife just recently died in her sleep. He was a pallbearer at Kim's funeral (the one from Mississippi). So far there is no known explanation for her death.
Yesterday, my husband told me that Steve called and told him that his long-time friend that was also a pallbearer at Kim's funeral is dead. He had confronted his wife with a gun, telling her to shoot him. She said no. He went to the neighbors and told them to call the police or he would shoot them. They did and in the confrontation the police shot him.
Oh my!
My husband says "things run in threes."??? I've never heard of that. If that's true then whatever is going on - its done. If not, my husband was a pallbearer and..........