Mr Siddiqi was stabbed at his family home on Ninian Road in Cardiff
The murder of a teenager in front of his parents at their family home is an "extremely unusual" case say police.
They say there is "no motive at this stage" for the stabbing of Aamir Siddiqi, 17, by two masked men on Sunday afternoon in Roath, Cardiff.
Officers said Mr Siddiqi's family were "understandably going through an unbelievably traumatic time."
The A-level student was described as "a gentleman" and as "kind, sensitive and really funny" by his family.
Police said two men armed with a "bladed weapon" forced their way into the end terrace house in Ninian Road in the city suburb of Roath at around 1340 BST.
His parents, aged 55 and 68, were also injured as they tried to protect their son.
South Wales Police are seeking two men, both of Asian appearance, seen leaving the area at the time.
One is described as being in his late 20s, of average height, with a stocky build. He had dark hair and was wearing dark clothing.
The other was in his early 20s, of slim build, and 5ft 11ins (1.8m) tall. He was wearing a white jacket with a grey stripe down the sleeves.
As they were leaving the area they were seen pulling black knitted balaclavas over their faces, said police.
Officers said they were unsure about any motive at present.
Divisional commander for Cardiff, Chief Supt Bob Tooby said: "This was an extremely serious and unusual incident and I wish to reassure residents and the wider community that a full investigation is ongoing to arrest those responsible.
Police say "extensive investigations" are ongoing
"Aamir's family and friends are understandably going through an unbelievably traumatic time and we at South Wales Police are doing all we can to support them."
In a statement released through police, his family said: "Aamir was passionate about sport and especially cricket, American football, and football. He liked to commentate as well as participate.
"He was keen on current events and politics and wanted to do law and had a place at Cardiff University after his exams.
"He was like his dad - he was a gentleman, kind and sensitive and really funny."
Anyone with information is asked to contact the incident room at Cardiff Central Police Station on 02920 571530 or Crimestoppers anonymously on 0800 555 111.