If they were all in the same load, something must have fallen into/got mixed with the load, such as ink pen, etc. Full washer with hot water and add cleaning agent such as ammonia or plain detergent to clean the washer cycle.
To clean those shirts, add a 1/4 c of "Simply Green" / The Green Stuff ($ store brand) to temp appropriate water, directly spray on spots and let soak a few minutes, then wash (with or without detergent) and do a double rinse cycle. Naptha or Zote laundry BAR soap are good as "detergent". HTH