John "Rocky" Whelan was born around 1800 in Wexford, Ireland, though some records list 1816 as a possibility. Early descriptions show him as an imposing figure: tall (6'1") and heavy-set, with craggy, pock-marked features—earning him the nickname “Rocky”. 

In 1827 or 1829 (accounts vary), Whelan was sentenced in the Chester or Wexford Quarter Sessions for theft and transported to Australia aboard the Marquis of Hastings or Larkins—arriving in Sydney that same year. He quickly resumed a criminal path, taken into custody for highway robbery in Sydney, then sent to Norfolk Island after being involved in a failed mutiny or seizure of the brig Governor Phillip. 

On Norfolk Island, he amassed a long record of offenses—at least 40 documented crimes—and endured 700 lashes. When Norfolk Island's penal station closed in 1853, Whelan was transferred back to Tasmania—initially assigned to a work gang in Hobart that he abandoned after just two days. On 28 January 1854, he escaped Port Arthur, slipping past guard dogs at Eaglehawk Neck, and vanished into the wilds of Mount Wellington, where he took refuge in a cave that still bears his name—Rocky Whelan’s Cave. 

Once freed in the bush, Whelan teamed up with Peter Connolly, a fellow escapee from Norfolk Island. Together they became notorious for highway robbery and murder, targeting lone travelers and isolated homesteads throughout Tasmania’s wild terrain.

His breaking point came when Magistrate Dunn—a storekeeper from Franklin—was walking home from Hobart. Whelan robbed, murdered, and stripped him, presumably for boots, then left the body some distance into the Huon track. Legend says the boots had holes, and after stealing Dunn’s, Whelan took money for repairs, only to wear the very boots of his victim. The bootmaker recognized them, and the police were ready when Rocky returned to collect them. 

Whelan was captured on 19 May 1855 in Hobart outside a bootmaker’s shop. He was carrying a loaded double-barreled pistol (that miraculously failed to fire) and brandishing £16 in cash. 

While awaiting trial, he made a chilling confession—acknowledging the murders of at least five men: Magistrate Dunn, William Grace near Brown’s River, elderly Thomas Axford near Bagdad, and two other unnamed victims. He provided details that allowed the police to discover Dunn’s decomposed body in a ravine—face shattered and bones driven through the skull, remains mutilated by wildlife.

He also admitted to armed robberies of William Kearney (at Grass Tree Hill) and Richard Carpenter (at North West Bay), during which he menacingly brandished pistols for theft.

Rocky was tried and sentenced to death. On 26 June 1855, he was executed by hanging at Hobart Gaol, lining the gallows alongside Peter Connolly, Edward Heylin, and John Parsons Knights.