調查過程
1) 警察兇殺組分析後認為,藏屍紙盒底部雖然經過拖拉但損毀輕微,初步鎖定兇殺案的第一現場在跑馬地附近,但他們盤查了將近800人仍無線索、包括調問附近750多個電器行店員。當時傳言卞為夜校追求不果者或吃醋者所殺。但一切都沒結果、警方茫無頭緒。
a. 反對殺人:歐陽炳強難以一個人將紙箱+屍體無損地從閣樓搬去店外,即刻連警員去案件重演都極為困難,一係炳強就要將裸體女屍獨自搬去門外紙箱,真係會係電車站(當時應該係最受歡迎既交通工具)到做咁癲既野?如果真係咁樣搬,會唔會身體上得咁少纖維?
2) 警方甚至找警員深夜扮鬼聲電話嚇歐陽炳強,但他仍沒反應,第二天照常上班。可是「光頭神探」貝亞堅持歐陽炳強是案中兇手,鎖定調查前後三個月。
a. 反對殺人:搵人跟蹤佢,但完全冇任何可疑,冇睇到佢有異常/搵下一個獵物
b. 支持殺人:佢呢家知道風頭火勢,收埋左
3) 警方測試當年市面上常見的50款私家車,發覺所有車款的坐位或車尾空間,都不能容納這款日立牌17寸電視機紙箱,所以排除藏屍紙盒是由普通私家車運到現場。如果兇手可以用貨車運送屍箱,為何不運至郊外棄屍?而選擇跑馬地黃泥涌道這種市區大街來棄置?所以推斷兇案很可能是發現紙箱附近的某地點。
a. 反對殺人:點解唔可以用小型貨車運送?可唔可以係有預謀老屈?
控方論據
1) 1. 最後聯絡死者的證人陳彬彬所作證供,稱1974年12月16日6:30pm,卞玉瑛在電話中告訴她,她已經身處跑馬地電車總站。陳彬彬收線後,5分鐘步行至電車總站卻不見卞玉瑛,並等待至7時才離去。估計死者在電車總站鄰近地方遭到毒手。藏屍的紙箱體積頗大,加上死者屍體的重量,難以移動運送,但紙箱卻整體無甚損壞,也沒證據被運輸過,所以再印證死者是就近電車站某處被殺害繼而被棄屍。而安美飲品公司符合這項條件。
2) 死者指甲中的纖維與歐陽炳強查獲的西裝上衣上的纖維相同。
3) 死者身上、安美飲品公司工場及歐陽炳強家中查獲的一件衣服上均發現相同但不知來源的綠色纖維各兩條。
1. 支持殺人:Two green fibres of unknown origin were found on the appellant's suit and these matched other fibres of unknown origin found on the body and on the workshop floor. The chemist was of opinion that they all came from the same source. (CACC528/1976 日期: 07/08/1976)
4) 死者頭髮上發現的銅碎與安美飲品公司工場內發現的相同,手臂上粘有的紙片與工場內所發現另一紙片同類。
反對殺人: 1. there is no evidence that the paper adhering to the girl's forearm came from the workshop.
5) 藏屍紙盒內找到白色油漆殘跡,與安美雪榚店工場的白色油漆殘跡相同,所以極大可能,屍體及紙盒曾經出現在安美飲品公司的工場。
1. 反對殺人:白色油應該係工場並唔罕見,但竟然第一兇案現場係冇任何血積,死者指模?
6) 從安美飲品公司經理及上班打卡機證實:歐陽炳強是1974年12月16日當晚唯一當值人。他也是其中擁有安美飲品公司3條大門鐵閘鎖匙的員工之一。
7) 有兩個品格證人證明歐陽炳強有變態行為,曾經兩次以煙頭灼燒少女衫裙。坊間有傳二人為卞玉瑛夜校同學,但法庭記錄顯示兩名證人都是在觀塘區工作的工廠工人。
1. Miss Yip Kit Ngan and Miss Tang Shui Pik: having holes burned in her skirt with a lighted cigarette when she was travelling on a ferry whilst the other girl was a witness to both incidents
2. Miss Yip, and her friend, were shown photographs of four men by police. One of these was the appellant and each girl picked him out. However, the photographs of the other three men were in black and white whereas that of the appellant was coloured. (CACC528/1976 日期: 07/08/1976)
3. The day after that the girls went again to the police station and again picked out the appellant from photographs. This time the "parade" consisted of eight photographs and all were in black and white.
4. 反對殺人:Miss Yip, the victim of the two skirt incidents, lives with her elder brother. He runs a small restaurant at the end of the street in which the deceased lived. He and the deceased were, because of this, quite well acquainted with each other
a. 反對殺人:竟然出黎指證歐陽炳強既女仔,竟然咁巧合地,個阿哥係附近做大排檔,而又識死者?呢個男士會唔會更加有動機殺害女死者呢?
8) 野食論:the contents of the stomach were largely identical with the meal which the girl had taken at her home at 1 p.m. and whilst it is undesirable to speculate upon what the jury decided upon this matter, it was certainly open to them, in the context of the whole of the evidence, to conclude that the contents of the stomach represented the meal commenced about 1 p.m. (CACC528/1976 日期: 07/08/1976)
1. 支持殺人:有法醫證實大部分既食物都係同1點食既野相同,所以未必一定有進食過
辯方及堅持歐陽無罪的支持者提出了很多零碎的疑點,例如
6. 警方僅集中調查歐陽炳強一人,對被告不公。
a. 反對殺人:clothing of other employees in the shop and workshop had not been analysed, the investigations having been focused exclusively upon the Appellant once he came under suspicion
7. 歐陽炳強夫妻恩愛、有一女,妻子懷孕;任職政府文員,職業穩定;與受害人不相識,找不到確切的殺人動機。
a. 支持殺人:只係基本人品證明,有案例係互不相識都照殺
b. 反對殺人:對卞玉瑛沒有實際殺人動機
8. 受害人死亡時間一改再改,似為遷就案發可能。(後來法醫指出因死者是被勒死,體溫下降的速度會減慢,擴大死亡時間的範圍)
9. 紙盒上的指紋不是歐陽炳強的。
a. 支持殺人:會唔會係炳強一早抹走晒?
10. 當日卞玉瑛的夜校簽到簿碰巧不翼而飛。
a. Attendance register of the evening school which she normally attended but failed to reach on the night of her death. was found after her death to be missing, a matter minor in itself but possibly pointing a finger at somebody else rather than at the Appellant who had no association with her school
b. 反對殺人:如果兇手係另有其他人,例如夜校壞同學及其壞分子,咁簽到簿就係好關鍵,但竟然警察冇係呢方面解釋,例如係咪問晒所有夜校人士作證有冇咩同學冇返學。