When Thomas Walker was admitted to Newcastle Gaol from Maitland on 16 May 1836 his ship of arrival was given as Eliza and year of arrival 1834 *. He was stated to be a native of Yorkshire and occupation tailor.
He was charged with bushranging and murder and sent for trial at the Supreme Court in Sydney on 19 May 1836.  He was sent to Sydney Gaol from Newcastle gaol to await trial on 19 May 1836. 
Indicted for Murder
Thomas Walker, an assigned servant to Henry Dangar, was indicted for murdering bushranger John Poole, by shooting him at New England, on the 23rd of April 1836. ........
The Attorney-General in opening the case said, that the murdered man John Poole was a bushranger, and the prisoner was in commission with him, and had deliberately shot him. Although by law, any Constable or other free person was authorised to shoot a bushranger if he had no other means of detaining him; if a person in connexion with bushrangers deliberately kill one of them, it was certainly murder.
Hugh O'Neil. - I am a private in the Mounted Police; in April last I was on duty at Colonel Dumaresq's; I heard that bushrangers used to be harboured at Mr. Dangar's station, about five or six miles from Dumaresq's. I went there in company with another private and a sergeant. The prisoner at the bar was shepherd there; I found him at some distance from the station with some stolen property in his possession, at eight o'clock in the morning; he had two jackets and a pair of trousers on his arm, with Colonel Dumaresq's marks on, I apprehended him.
He (Thomas Walker) said that the bushrangers had given him the things, and that they were to rob Mr. Cory's and Mr. Chilcott's station the day after. These stations were about twelve miles from Mr. Dangar's. We went to Cory's station and remained there all day, at night we left the station and encamped in the bush. We heard of their committing more robberies at Dumaresq's, and as the prisoner was only hindering us, we let him go at large. We came up with the bushrangers on the morning of the 23rd April, when they were robbing Mr. Dumaresq's station a third time.
We were in the house when they came up and went out; we had left our horses away from the house; two of the bushrangers had horses; there was one on foot, who went towards Danger's station, we fired at them but they escaped. We proceeded to Dangar's station; on the road we found a jacket. The prisoner had no jacket, he said that the bushrangers had been there and taken his jacket away from him. The next morning we again went to the station; the prisoner had a musket and fowling piece, which he held up as we rode up and said, here they are.
We took him into custody again, and he told us he shot one of the bushrangers that morning. He said that one of the bushrangers came to the hut at three o'clock in the morning, and forced him to go along with him to rob one of Mr. John Dangar's stations. On the road, the bushranger, James Poole, was tired and laid down, leaving him (the prisoner), to keep watch and see that the Police did not come down, and that while he was asleep he shot him dead. He said the man never moved.
I asked him why he shot him, and he said to save himself. The prisoner accompanied us to the spot where the body was lying in the bush. We stripped the body, the wound was through the heart. He did not tell me he had shot the man until we had taken him in charge. We found two blankets, some powder and shot, and things lying near the body. 
Thomas Walker was found guilty at trial and ordered for execution which took place on 18 November 1836 at Sydney
.....On Friday, the utmost penalty of the law was carried into effect upon the person of Thomas Walker, convicted during the last sitting of the Supreme Court, of the wilful murder of a bushranger who was at large with him. The culprit was attended by the Rev. William Cowper, to whose religious consolation, he appeared to pay considerable attention. Every arrangement having been made, the fatal signal was given, and the law was avenged.
Notes and Links
1). Sydney Herald 7 November 1836
2). Newcastle Gaol Entrance Books. State Archives Roll 136. (Ancestry)
3). Sydney Gaol Entrance Books. State Archives Roll 852 (Ancestry)
4). Sydney Gazette 22 November 1836
5) * There was no convict ship Eliza arriving in 1834