How did Ixolite know the advert was a clue for him? Solve the code and tell me who Ixolite arrested.

Question

Inspector Ixolite of the Yard was investigating a murder at Nottonmye Manor.
It was a difficult case, and Ixolite was completely stumped until he noticed a message sent to him by the killer cunningly hidden in a newspaper advertisement selling Car Licence Plates.
Inspector Ixolite thought about it for a while, and when he had solved the puzzle, immediately arrested the guilty man.

Q1) How did Ixolite know the advert was a clue for him?

Q2) Solve the code and tell me who Ixolite arrested.

This is the newspaper advert (Car licence plates for sale) that Inspector Ixolite saw.

Plates For Sale;

[W 05 NWO]
[H 13 HSR ]
[O 05 EBM]
[D 08 UNE]
[U 10 HTY]
[N 04 BRE]
[N 16 TTE]
[I 26 LHC ]
[T 10 AEE]
[I 26 CNA]
[X 22 VDA]

Answer 1

1)The first bit is easy, as the first letter of each plate spells WHODUNNIT IX
(A challenge to our Inspector.)

2)The second bit is a little trickier, but I gave you the solution.
If you read the last three letters in each plate from the bottom up and right to left you get
ADVANCE EACH LETTER BY THE NUMBER SHOWN, so advance W by 5 to get B,
H by 13 to get U and so on until you spell BUTLER DID IT.

Answer 2

WHODUNNIT
. ADVANCE EACH LETTER BY THE NUMBER A SHOWN BY IT
W05 is B
H13 is U
O05 is T
D08 is L
U10 is E
N04 is R
N16 is D
I26 is I
T10 is D
I26 is I
X22 is T
So BUTLER DID IT.
THE OFFICER ARRESTED THE BUTLER.