Follow these steps to transform the sentences given as examples from direct speech to indirect speech.
"What's suspicious about that?" Mrs. Brown asked.
Mrs. Brown asked what was suspicious about that.
"What do you make of the four words, Leroy?"
Mrs. Brown questioned Leroy what he made of the four words.
"Wasn't he mixed up in a jewellery robbery a few years ago?"
Mrs. Brown inquired whether he had been mixed up in a jewellery robbery a few years before.
"Didn't you search Nolan's house, dear?"
Mrs. Brown asked Chief Brown whether he had searched Nolan's house.
"Is there a young fir tree in Mr. Nolan's palm-tree nursery?"
Mrs. Brown inquired whether there was a young fir tree in Mr. Nolan's palm-tree nursery.
Explanation
((i)) Wh-question: 'What' is retained, 's' changes to 'was', 'that' remains 'that'. ((ii)) Wh-question: 'you' changes to 'he', 'do make' changes to 'made'. ((iii)) Yes/No question: 'whether' is added, 'ago' changes to 'before', tense shifts to past perfect. ((iv)) Yes/No question: 'whether' is added, 'you' changes to 'he', tense shifts to past perfect. ((v)) Yes/No question: 'whether' is added, 'is' changes to 'was'.