To see if Atticus is responsible
jem and dill
Dill told Atticus that they were just having lunch.
Dill technically lied to Atticus by saying that they were playing strip poker, but not with cards
If you're asking about when Scout and Jem find Dill under the bed, then Jem was the one who went to Atticus and told him that Dill had come.
Dill and Jem see the shadow of Atticus Finch when Jem is on the porch of the house.
Jem decides to sneak out with Scout and Dill to find Atticus. Jem is Scout's brother in To Kill A Mockingbird.
In "To Kill a Mockingbird," Jem's loss of innocence is symbolized by his reaction to Tom Robinson's trial and the injustice that he witnesses. Jem's realization of the deep-rooted racism in their society shatters his beliefs in fairness and equality, marking the end of his childhood naivety.
Atticus suggests that Dill should be allowed to stay with them for the summer to keep him safe and out of trouble. He believes that having Dill around will give him a structured environment and positive influences. Additionally, Atticus feels that being with Scout and Jem will offer Dill stability and a sense of family.
Dill explains Jem's missing plants by first saying they were playing strip poker by the fish pond. Dill then said they were lighting matches to explain the missing plants.
When Dill ran away and came to Scout for help she was prepared to hide him. When Jem found out, he immediately told Atticus, thus driving a deeper wedge between Jem and Scout.
Jem told on her and Dill, and let Atticus know that Dill was under Scout's bed and had run away. The last remaining code of their childhood was that they never tell Atticus their secrets.
Jem helps Atticus search for Dill when he runs away by informing the sheriff and looking for him around town. He also keeps an eye out for Dill's return at the Finch house.